diff --git a/README.md b/README.md
index ff30bd1..95b3ad4 100644
--- a/README.md
+++ b/README.md
@@ -76,7 +76,8 @@ TimescaleDB schema is initialized from `db/init/001_schema.sql` and includes:
 - `observations_ws90` (hypertable): raw WS90 observations with payload metadata, plus the full JSON payload (`payload_json`).
 - `observations_baro` (hypertable): barometric pressure observations from other MQTT topics.
 - `forecast_openmeteo_hourly` (hypertable): hourly forecast points keyed by `(site, model, retrieved_at, ts)`.
-- `predictions_rain_1h` (hypertable): model probability + decision + realized outcome fields.
+- `predictions_rain_1h` (hypertable): legacy 1-hour model probability + decision + realized outcome fields.
+- `predictions_rain_4h` (hypertable): 4-hour model probability + decision + realized outcome fields.
 - Continuous aggregates:
   - `cagg_ws90_1m`: 1‑minute rollups (avg/min/max for temp, humidity, wind, uvi, light, rain).
   - `cagg_ws90_5m`: 5‑minute rollups (same metrics as `cagg_ws90_1m`).
@@ -86,14 +87,18 @@ Retention/compression:
 - `observations_baro` has a 90‑day retention policy and compression after 7 days.
 
 ### Existing databases
-If you’re on an existing database, you’ll need to apply the new table definition once (the init SQL only runs on a fresh DB). Example:
+If you’re on an existing database, apply the 4-hour prediction table migration:
+
+```sh
+docker compose exec -T timescaledb psql -U postgres -d micrometeo -f /docker-entrypoint-initdb.d/003_rain_predictions_4h.sql
+```
+
+If you also need to backfill older schema objects, you can still re-run:
 
 ```sh
 docker compose exec -T timescaledb psql -U postgres -d micrometeo -f /docker-entrypoint-initdb.d/001_schema.sql
 ```
 
-Or copy just the `observations_baro` section into a manual `psql -c`.
-
 For rain-model monitoring views, also apply `db/init/002_rain_monitoring_views.sql` on existing DBs:
 
 ```sh
diff --git a/cmd/ingestd/web.go b/cmd/ingestd/web.go
index f54841f..ebb616e 100644
--- a/cmd/ingestd/web.go
+++ b/cmd/ingestd/web.go
@@ -179,16 +179,29 @@ func (s *webServer) handleDashboard(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	const rainModelName = "rain_next_1h"
+	const rainModelName = "rain_next_4h"
+	const rainModelHorizonHours = 4
 
-	latestRainPrediction, err := s.db.LatestRainPrediction(r.Context(), s.site.Name, rainModelName)
+	latestRainPrediction, err := s.db.LatestRainPrediction(
+		r.Context(),
+		s.site.Name,
+		rainModelName,
+		rainModelHorizonHours,
+	)
 	if err != nil {
 		http.Error(w, "failed to query latest rain prediction", http.StatusInternalServerError)
 		log.Printf("web dashboard latest rain prediction error: %v", err)
 		return
 	}
 
-	rainPredictionRange, err := s.db.RainPredictionSeriesRange(r.Context(), s.site.Name, rainModelName, start, end)
+	rainPredictionRange, err := s.db.RainPredictionSeriesRange(
+		r.Context(),
+		s.site.Name,
+		rainModelName,
+		rainModelHorizonHours,
+		start,
+		end,
+	)
 	if err != nil {
 		http.Error(w, "failed to query rain predictions", http.StatusInternalServerError)
 		log.Printf("web dashboard rain prediction range error: %v", err)
diff --git a/cmd/ingestd/web/app.js b/cmd/ingestd/web/app.js
index 9988a73..577547a 100644
--- a/cmd/ingestd/web/app.js
+++ b/cmd/ingestd/web/app.js
@@ -979,7 +979,7 @@ function renderDashboard(data) {
     data: {
       datasets: [
         {
-          label: rainPredictions.length ? "model rain probability (%)" : "heuristic rain probability (%)",
+          label: rainPredictions.length ? "model rain probability next 4h (%)" : "heuristic rain probability (%)",
           data: rainPredictions.length ? buildRainProbabilitySeriesFromPredictions(rainPredictions) : buildRainProbabilitySeries(obsFiltered),
           borderColor: colors.rain,
           backgroundColor: "rgba(78, 168, 222, 0.18)",
diff --git a/cmd/ingestd/web/index.html b/cmd/ingestd/web/index.html
index 7bbf807..34dd1d2 100644
--- a/cmd/ingestd/web/index.html
+++ b/cmd/ingestd/web/index.html
@@ -70,7 +70,7 @@
             <div class="value" id="live-pressure">--</div>
           </div>
           <div class="metric">
-            <div class="label">Rain 1h %</div>
+            <div class="label">Rain 4h %</div>
             <div class="value" id="live-rain-prob">--</div>
           </div>
           <div class="metric">
diff --git a/db/init/001_schema.sql b/db/init/001_schema.sql
index b8d85fd..1117141 100644
--- a/db/init/001_schema.sql
+++ b/db/init/001_schema.sql
@@ -112,6 +112,34 @@ CREATE INDEX IF NOT EXISTS idx_predictions_rain_1h_site_ts
 CREATE INDEX IF NOT EXISTS idx_predictions_rain_1h_pending_eval
   ON predictions_rain_1h(site, evaluated_at, ts DESC);
 
+-- Rain model predictions (next 4h)
+CREATE TABLE IF NOT EXISTS predictions_rain_4h (
+  ts                    TIMESTAMPTZ NOT NULL,
+  generated_at          TIMESTAMPTZ NOT NULL DEFAULT now(),
+  site                  TEXT NOT NULL,
+  model_name            TEXT NOT NULL,
+  model_version         TEXT NOT NULL,
+  threshold             DOUBLE PRECISION NOT NULL,
+  probability           DOUBLE PRECISION NOT NULL,
+  predict_rain          BOOLEAN NOT NULL,
+
+  rain_next_4h_mm_actual DOUBLE PRECISION,
+  rain_next_4h_actual    BOOLEAN,
+  evaluated_at           TIMESTAMPTZ,
+
+  metadata              JSONB,
+
+  PRIMARY KEY (site, model_name, model_version, ts)
+);
+
+SELECT create_hypertable('predictions_rain_4h', 'ts', if_not_exists => TRUE);
+
+CREATE INDEX IF NOT EXISTS idx_predictions_rain_4h_site_ts
+  ON predictions_rain_4h(site, ts DESC);
+
+CREATE INDEX IF NOT EXISTS idx_predictions_rain_4h_pending_eval
+  ON predictions_rain_4h(site, evaluated_at, ts DESC);
+
 -- Raw retention: 90 days
 DO $$
 BEGIN
diff --git a/db/init/002_rain_monitoring_views.sql b/db/init/002_rain_monitoring_views.sql
index 5945af8..1a06467 100644
--- a/db/init/002_rain_monitoring_views.sql
+++ b/db/init/002_rain_monitoring_views.sql
@@ -100,44 +100,104 @@ FROM baseline;
 
 
 CREATE OR REPLACE VIEW rain_prediction_drift_daily AS
+WITH all_predictions AS (
+  SELECT
+    1::INT AS horizon_hours,
+    ts,
+    site,
+    model_name,
+    model_version,
+    threshold,
+    probability,
+    predict_rain
+  FROM predictions_rain_1h
+  UNION ALL
+  SELECT
+    4::INT AS horizon_hours,
+    ts,
+    site,
+    model_name,
+    model_version,
+    threshold,
+    probability,
+    predict_rain
+  FROM predictions_rain_4h
+)
 SELECT
   time_bucket(INTERVAL '1 day', ts) AS day,
   site,
   model_name,
   model_version,
+  horizon_hours,
   count(*) AS prediction_rows,
   avg(probability) AS probability_mean,
   stddev_samp(probability) AS probability_stddev,
   avg(CASE WHEN predict_rain THEN 1.0 ELSE 0.0 END) AS predicted_positive_rate,
   avg(threshold) AS threshold_mean
-FROM predictions_rain_1h
-GROUP BY 1,2,3,4;
+FROM all_predictions
+GROUP BY 1,2,3,4,5;
 
 
 CREATE OR REPLACE VIEW rain_calibration_drift_daily AS
+WITH all_predictions AS (
+  SELECT
+    1::INT AS horizon_hours,
+    ts,
+    site,
+    model_name,
+    model_version,
+    probability,
+    predict_rain,
+    rain_next_1h_actual AS rain_actual
+  FROM predictions_rain_1h
+  UNION ALL
+  SELECT
+    4::INT AS horizon_hours,
+    ts,
+    site,
+    model_name,
+    model_version,
+    probability,
+    predict_rain,
+    rain_next_4h_actual AS rain_actual
+  FROM predictions_rain_4h
+)
 SELECT
   time_bucket(INTERVAL '1 day', ts) AS day,
   site,
   model_name,
   model_version,
-  count(*) FILTER (WHERE rain_next_1h_actual IS NOT NULL) AS evaluated_rows,
-  avg(probability) FILTER (WHERE rain_next_1h_actual IS NOT NULL) AS mean_probability,
-  avg(CASE WHEN rain_next_1h_actual THEN 1.0 ELSE 0.0 END) FILTER (WHERE rain_next_1h_actual IS NOT NULL) AS observed_positive_rate,
-  avg(power(probability - CASE WHEN rain_next_1h_actual THEN 1.0 ELSE 0.0 END, 2.0))
-    FILTER (WHERE rain_next_1h_actual IS NOT NULL) AS brier_score,
+  horizon_hours,
+  count(*) FILTER (WHERE rain_actual IS NOT NULL) AS evaluated_rows,
+  avg(probability) FILTER (WHERE rain_actual IS NOT NULL) AS mean_probability,
+  avg(CASE WHEN rain_actual THEN 1.0 ELSE 0.0 END) FILTER (WHERE rain_actual IS NOT NULL) AS observed_positive_rate,
+  avg(power(probability - CASE WHEN rain_actual THEN 1.0 ELSE 0.0 END, 2.0))
+    FILTER (WHERE rain_actual IS NOT NULL) AS brier_score,
   avg(
     CASE
-      WHEN rain_next_1h_actual IS NULL THEN NULL
-      WHEN predict_rain = rain_next_1h_actual THEN 1.0
+      WHEN rain_actual IS NULL THEN NULL
+      WHEN predict_rain = rain_actual THEN 1.0
       ELSE 0.0
     END
   ) AS decision_accuracy
-FROM predictions_rain_1h
-GROUP BY 1,2,3,4;
+FROM all_predictions
+GROUP BY 1,2,3,4,5;
 
 
 CREATE OR REPLACE VIEW rain_pipeline_health AS
-WITH sites AS (
+WITH prediction_latest AS (
+  SELECT
+    site,
+    max(generated_at) AS prediction_generated_latest_ts,
+    max(evaluated_at) AS prediction_evaluated_latest_ts
+  FROM (
+    SELECT site, generated_at, evaluated_at FROM predictions_rain_1h
+    UNION ALL
+    SELECT site, generated_at, evaluated_at FROM predictions_rain_4h
+  ) p
+  GROUP BY site
+),
+sites AS (
   SELECT DISTINCT site FROM observations_ws90
   UNION
   SELECT DISTINCT site FROM observations_baro
@@ -145,12 +205,16 @@ WITH sites AS (
   SELECT DISTINCT site FROM forecast_openmeteo_hourly
   UNION
   SELECT DISTINCT site FROM predictions_rain_1h
+  UNION
+  SELECT DISTINCT site FROM predictions_rain_4h
 )
 SELECT
   s.site,
   (SELECT max(ts) FROM observations_ws90 w WHERE w.site = s.site) AS ws90_latest_ts,
   (SELECT max(ts) FROM observations_baro b WHERE b.site = s.site) AS baro_latest_ts,
   (SELECT max(ts) FROM forecast_openmeteo_hourly f WHERE f.site = s.site) AS forecast_latest_ts,
-  (SELECT max(generated_at) FROM predictions_rain_1h p WHERE p.site = s.site) AS prediction_generated_latest_ts,
-  (SELECT max(evaluated_at) FROM predictions_rain_1h p WHERE p.site = s.site) AS prediction_evaluated_latest_ts
-FROM sites s;
+  p.prediction_generated_latest_ts,
+  p.prediction_evaluated_latest_ts
+FROM sites s
+LEFT JOIN prediction_latest p
+  ON p.site = s.site;
diff --git a/db/init/003_rain_predictions_4h.sql b/db/init/003_rain_predictions_4h.sql
new file mode 100644
index 0000000..8de62a0
--- /dev/null
+++ b/db/init/003_rain_predictions_4h.sql
@@ -0,0 +1,29 @@
+-- Add 4-hour rain prediction storage table.
+-- Safe to re-run.
+
+CREATE TABLE IF NOT EXISTS predictions_rain_4h (
+  ts                    TIMESTAMPTZ NOT NULL,
+  generated_at          TIMESTAMPTZ NOT NULL DEFAULT now(),
+  site                  TEXT NOT NULL,
+  model_name            TEXT NOT NULL,
+  model_version         TEXT NOT NULL,
+  threshold             DOUBLE PRECISION NOT NULL,
+  probability           DOUBLE PRECISION NOT NULL,
+  predict_rain          BOOLEAN NOT NULL,
+
+  rain_next_4h_mm_actual DOUBLE PRECISION,
+  rain_next_4h_actual    BOOLEAN,
+  evaluated_at           TIMESTAMPTZ,
+
+  metadata              JSONB,
+
+  PRIMARY KEY (site, model_name, model_version, ts)
+);
+
+SELECT create_hypertable('predictions_rain_4h', 'ts', if_not_exists => TRUE);
+
+CREATE INDEX IF NOT EXISTS idx_predictions_rain_4h_site_ts
+  ON predictions_rain_4h(site, ts DESC);
+
+CREATE INDEX IF NOT EXISTS idx_predictions_rain_4h_pending_eval
+  ON predictions_rain_4h(site, evaluated_at, ts DESC);
diff --git a/docker-compose.yml b/docker-compose.yml
index 5b76f5c..b275c4f 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -34,8 +34,9 @@ services:
     environment:
       DATABASE_URL: "postgres://postgres:postgres@timescaledb:5432/micrometeo?sslmode=disable"
       RAIN_SITE: "home"
-      RAIN_MODEL_NAME: "rain_next_1h"
-      RAIN_MODEL_VERSION_BASE: "rain-auto-v1-extended"
+      RAIN_HORIZON_HOURS: "4"
+      RAIN_MODEL_NAME: "rain_next_4h"
+      RAIN_MODEL_VERSION_BASE: "rain-auto-v2-extended-4h"
       RAIN_MODEL_FAMILY: "auto"
       RAIN_FEATURE_SET: "extended"
       RAIN_FORECAST_MODEL: "ecmwf"
diff --git a/docs/rain_model_runbook.md b/docs/rain_model_runbook.md
index 0c01a0a..24f3798 100644
--- a/docs/rain_model_runbook.md
+++ b/docs/rain_model_runbook.md
@@ -4,6 +4,14 @@ Operational guide for training, evaluating, deploying, monitoring, and rolling b
 
 ## 1) One-time Setup
 
+Apply 4-hour prediction table migration:
+
+```sh
+docker compose exec -T timescaledb \
+  psql -U postgres -d micrometeo \
+  -f /docker-entrypoint-initdb.d/003_rain_predictions_4h.sql
+```
+
 Apply monitoring views:
 
 ```sh
@@ -21,6 +29,7 @@ python scripts/train_rain_model.py \
   --site "home" \
   --start "2026-02-01T00:00:00Z" \
   --end "2026-03-03T23:55:00Z" \
+  --horizon-hours 4 \
   --feature-set "extended" \
   --model-family "auto" \
   --forecast-model "ecmwf" \
@@ -29,7 +38,7 @@ python scripts/train_rain_model.py \
   --calibration-methods "none,sigmoid,isotonic" \
   --threshold-policy "walk_forward" \
   --walk-forward-folds 4 \
-  --model-version "rain-auto-v1-extended" \
+  --model-version "rain-auto-v2-extended-4h" \
   --out "models/rain_model.pkl" \
   --report-out "models/rain_model_report.json" \
   --model-card-out "models/model_card_{model_version}.md" \
@@ -53,7 +62,8 @@ Review in report:
 python scripts/predict_rain_model.py \
   --site home \
   --model-path "models/rain_model.pkl" \
-  --model-name "rain_next_1h" \
+  --model-name "rain_next_4h" \
+  --horizon-hours 4 \
   --dry-run
 ```
 
@@ -63,7 +73,8 @@ python scripts/predict_rain_model.py \
 python scripts/predict_rain_model.py \
   --site home \
   --model-path "models/rain_model.pkl" \
-  --model-name "rain_next_1h"
+  --model-name "rain_next_4h" \
+  --horizon-hours 4
 ```
 
 ## 4) Rollback
@@ -72,6 +83,7 @@ python scripts/predict_rain_model.py \
 2. If promotion fails or no candidate model is produced, the worker keeps the active model unchanged.
 3. If inference starts without `RAIN_MODEL_PATH` but backup exists, the worker restores from backup automatically.
 4. Keep failed candidate artifacts for postmortem.
+5. During 4-hour rollout stabilization, keep `predictions_rain_1h` and `rain_next_1h` model artifacts available for immediate fallback.
 
 ## 5) Monitoring
 
@@ -118,12 +130,13 @@ Use the health-check script in cron, systemd timer, or your alerting scheduler:
 ```sh
 python scripts/check_rain_pipeline_health.py \
   --site home \
-  --model-name rain_next_1h \
+  --model-name rain_next_4h \
+  --horizon-hours 4 \
   --max-ws90-age 20m \
   --max-baro-age 30m \
   --max-forecast-age 3h \
   --max-prediction-age 30m \
-  --max-pending-eval-age 3h \
+  --max-pending-eval-age 6h \
   --max-pending-eval-rows 200
 ```
 
@@ -138,6 +151,7 @@ The script exits non-zero on failure, so it can directly drive alerting.
 - `RAIN_THRESHOLD_POLICY`
 - `RAIN_WALK_FORWARD_FOLDS`
 - `RAIN_ALLOW_EMPTY_DATA`
+- `RAIN_HORIZON_HOURS`
 - `RAIN_MODEL_BACKUP_PATH`
 - `RAIN_MODEL_CARD_PATH`
 
@@ -156,3 +170,88 @@ python scripts/recommend_rain_model.py \
   --top-k 5 \
   --json-out "models/rain_model_recommendation.json"
 ```
+
+## 9) Staged 4h Rollout Checklist
+
+Run this sequence in production/staging to satisfy the 4h cutover gate:
+
+1. Apply schema migration for 4h predictions:
+
+```sh
+docker compose exec -T timescaledb \
+  psql -U postgres -d micrometeo \
+  -f /docker-entrypoint-initdb.d/003_rain_predictions_4h.sql
+```
+
+2. Re-apply monitoring views (now include 1h + 4h unions):
+
+```sh
+docker compose exec -T timescaledb \
+  psql -U postgres -d micrometeo \
+  -f /docker-entrypoint-initdb.d/002_rain_monitoring_views.sql
+```
+
+3. Run a full 4h training/evaluation cycle and save report:
+
+```sh
+python scripts/train_rain_model.py \
+  --site "home" \
+  --start "2026-02-01T00:00:00Z" \
+  --end "2026-03-03T23:55:00Z" \
+  --horizon-hours 4 \
+  --feature-set "extended" \
+  --model-family "auto" \
+  --forecast-model "ecmwf" \
+  --tune-hyperparameters \
+  --threshold-policy "walk_forward" \
+  --walk-forward-folds 4 \
+  --model-version "rain-auto-v2-extended-4h" \
+  --out "models/rain_model_4h.pkl" \
+  --report-out "models/rain_model_report_4h.json"
+```
+
+4. Compare 4h metrics against the latest 1h benchmark report before switching dashboard defaults:
+
+```sh
+python scripts/compare_rain_reports.py \
+  --baseline "models/rain_model_report_1h.json" \
+  --candidate "models/rain_model_report_4h.json"
+```
+5. Run dry-run inference, then live inference with 4h model name/horizon:
+
+```sh
+python scripts/predict_rain_model.py \
+  --site home \
+  --model-path "models/rain_model_4h.pkl" \
+  --model-name "rain_next_4h" \
+  --horizon-hours 4 \
+  --dry-run
+
+python scripts/predict_rain_model.py \
+  --site home \
+  --model-path "models/rain_model_4h.pkl" \
+  --model-name "rain_next_4h" \
+  --horizon-hours 4
+```
+
+6. Validate health checks and dashboard data path for 4h:
+
+```sh
+python scripts/check_rain_pipeline_health.py \
+  --site home \
+  --model-name rain_next_4h \
+  --horizon-hours 4 \
+  --max-pending-eval-age 6h
+```
+
+7. Keep 1h path live in parallel until 4h drift/calibration remains stable for at least 7 days.
+
+### Fast rollback to 1h
+
+If 4h performance or pipeline health regresses:
+
+1. Set worker env back to:
+   `RAIN_HORIZON_HOURS=1`, `RAIN_MODEL_NAME=rain_next_1h`, and a known-good 1h model path/version.
+2. Restart `rainml` service.
+3. Confirm `check_rain_pipeline_health.py --horizon-hours 1 --model-name rain_next_1h` returns `ok`.
+4. Keep `predictions_rain_4h` data for postmortem; do not drop tables during rollback.
diff --git a/docs/rain_prediction.md b/docs/rain_prediction.md
index bc0277a..6cae8a0 100644
--- a/docs/rain_prediction.md
+++ b/docs/rain_prediction.md
@@ -1,14 +1,14 @@
-# Rain Prediction (Next 1 Hour)
+# Rain Prediction (Next 4 Hours)
 
 This project includes a baseline workflow for **binary rain prediction**:
 
-> **Will we see >= 0.2 mm of rain in the next hour?**
+> **Will we see >= 0.2 mm of rain in the next 4 hours?**
 
 It uses local observations (WS90 + barometer), trains a logistic regression
 baseline, and writes model-driven predictions back to TimescaleDB.
 
 ## P0 Decisions (Locked)
-- Target: `rain_next_1h_mm >= 0.2`.
+- Target: `rain_next_4h_mm >= 0.2`.
 - Primary use-case: low-noise rain heads-up signal for dashboard + alert candidate.
 - Frozen v1 training window (UTC): `2026-02-01T00:00:00Z` to `2026-03-03T23:55:00Z`.
 - Threshold policy: choose threshold on validation set by maximizing recall under
@@ -40,7 +40,7 @@ pip install -r scripts/requirements.txt
 - `scripts/train_rain_model.py`: strict time-based split training and metrics report, with optional
   validation-only hyperparameter tuning, calibration comparison, naive baseline comparison, and walk-forward folds.
 - `scripts/predict_rain_model.py`: inference using saved model artifact; upserts into
-  `predictions_rain_1h`.
+  `predictions_rain_4h`.
 - `scripts/run_rain_ml_worker.py`: long-running worker for periodic training + prediction.
 - `scripts/check_rain_pipeline_health.py`: freshness/failure check for alerting.
 - `scripts/recommend_rain_model.py`: rank saved training reports and recommend a deployment candidate.
@@ -60,7 +60,15 @@ Model-family options (`train_rain_model.py`):
 
 ## Usage
 ### 1) Apply schema update (existing DBs)
-`001_schema.sql` includes `predictions_rain_1h`.
+`003_rain_predictions_4h.sql` adds `predictions_rain_4h`.
+
+```sh
+docker compose exec -T timescaledb \
+  psql -U postgres -d micrometeo \
+  -f /docker-entrypoint-initdb.d/003_rain_predictions_4h.sql
+```
+
+`001_schema.sql` still remains safe to re-run for full schema parity.
 
 ```sh
 docker compose exec -T timescaledb \
@@ -76,6 +84,8 @@ docker compose exec -T timescaledb \
   -f /docker-entrypoint-initdb.d/002_rain_monitoring_views.sql
 ```
 
+All examples below assume a 4-hour horizon (`--horizon-hours 4`) and `model-name=rain_next_4h`.
+
 ### 2) Run data audit
 ```sh
 export DATABASE_URL="postgres://postgres:postgres@localhost:5432/micrometeo?sslmode=disable"
@@ -203,7 +213,8 @@ python scripts/train_rain_model.py \
 python scripts/predict_rain_model.py \
   --site home \
   --model-path "models/rain_model.pkl" \
-  --model-name "rain_next_1h"
+  --model-name "rain_next_4h" \
+  --horizon-hours 4
 ```
 
 ### 5) One-command P0 workflow
@@ -236,7 +247,7 @@ docker compose logs -f rainml
 - Model card: `models/model_card_<model_version>.md`
 - Model artifact: `models/rain_model.pkl`
 - Dataset snapshot: `models/datasets/rain_dataset_<model_version>_<feature_set>.csv`
-- Prediction rows: `predictions_rain_1h` (probability + threshold decision + realized
+- Prediction rows: `predictions_rain_4h` (probability + threshold decision + realized
   outcome fields once available)
 
 ### 7) Recommend deploy candidate from saved reports
diff --git a/internal/db/series.go b/internal/db/series.go
index 404dec0..0ffe848 100644
--- a/internal/db/series.go
+++ b/internal/db/series.go
@@ -51,11 +51,14 @@ type RainPredictionPoint struct {
 	GeneratedAt      time.Time  `json:"generated_at"`
 	ModelName        string     `json:"model_name"`
 	ModelVersion     string     `json:"model_version"`
+	HorizonHours     int        `json:"horizon_hours"`
 	Threshold        float64    `json:"threshold"`
 	Probability      float64    `json:"probability"`
 	PredictRain      bool       `json:"predict_rain"`
-	RainNext1hMM     *float64   `json:"rain_next_1h_mm_actual,omitempty"`
-	RainNext1hActual *bool      `json:"rain_next_1h_actual,omitempty"`
+	RainNextMM       *float64   `json:"rain_next_mm_actual,omitempty"`
+	RainNextActual   *bool      `json:"rain_next_actual,omitempty"`
+	RainNext1hMM     *float64   `json:"rain_next_1h_mm_actual,omitempty"` // backward-compatible alias
+	RainNext1hActual *bool      `json:"rain_next_1h_actual,omitempty"`    // backward-compatible alias
 	EvaluatedAt      *time.Time `json:"evaluated_at,omitempty"`
 }
 
@@ -365,8 +368,24 @@ func (d *DB) ForecastSeriesRange(ctx context.Context, site, model string, start,
 	}, nil
 }
 
-func (d *DB) LatestRainPrediction(ctx context.Context, site, modelName string) (*RainPredictionPoint, error) {
-	query := `
+func predictionStorageForHorizon(horizonHours int) (table string, mmCol string, flagCol string, err error) {
+	switch horizonHours {
+	case 1:
+		return "predictions_rain_1h", "rain_next_1h_mm_actual", "rain_next_1h_actual", nil
+	case 4:
+		return "predictions_rain_4h", "rain_next_4h_mm_actual", "rain_next_4h_actual", nil
+	default:
+		return "", "", "", fmt.Errorf("unsupported rain prediction horizon: %d", horizonHours)
+	}
+}
+
+func (d *DB) LatestRainPrediction(ctx context.Context, site, modelName string, horizonHours int) (*RainPredictionPoint, error) {
+	table, mmCol, flagCol, err := predictionStorageForHorizon(horizonHours)
+	if err != nil {
+		return nil, err
+	}
+
+	query := fmt.Sprintf(`
 		SELECT
 			ts,
 			generated_at,
@@ -375,15 +394,15 @@ func (d *DB) LatestRainPrediction(ctx context.Context, site, modelName string) (
 			threshold,
 			probability,
 			predict_rain,
-			rain_next_1h_mm_actual,
-			rain_next_1h_actual,
+			%s,
+			%s,
 			evaluated_at
-		FROM predictions_rain_1h
+		FROM %s
 		WHERE site = $1
 		  AND model_name = $2
 		ORDER BY ts DESC, generated_at DESC
 		LIMIT 1
-	`
+	`, mmCol, flagCol, table)
 
 	var (
 		p                              RainPredictionPoint
@@ -393,7 +412,7 @@ func (d *DB) LatestRainPrediction(ctx context.Context, site, modelName string) (
 		predictRain                    sql.NullBool
 	)
 
-	err := d.Pool.QueryRow(ctx, query, site, modelName).Scan(
+	err = d.Pool.QueryRow(ctx, query, site, modelName).Scan(
 		&p.TS,
 		&p.GeneratedAt,
 		&p.ModelName,
@@ -421,14 +440,22 @@ func (d *DB) LatestRainPrediction(ctx context.Context, site, modelName string) (
 	if predictRain.Valid {
 		p.PredictRain = predictRain.Bool
 	}
-	p.RainNext1hMM = nullFloatPtr(rainMM)
-	p.RainNext1hActual = nullBoolPtr(rainActual)
+	p.HorizonHours = horizonHours
+	p.RainNextMM = nullFloatPtr(rainMM)
+	p.RainNextActual = nullBoolPtr(rainActual)
+	p.RainNext1hMM = p.RainNextMM
+	p.RainNext1hActual = p.RainNextActual
 	p.EvaluatedAt = nullTimePtr(evaluatedAt)
 	return &p, nil
 }
 
-func (d *DB) RainPredictionSeriesRange(ctx context.Context, site, modelName string, start, end time.Time) ([]RainPredictionPoint, error) {
-	query := `
+func (d *DB) RainPredictionSeriesRange(ctx context.Context, site, modelName string, horizonHours int, start, end time.Time) ([]RainPredictionPoint, error) {
+	table, mmCol, flagCol, err := predictionStorageForHorizon(horizonHours)
+	if err != nil {
+		return nil, err
+	}
+
+	query := fmt.Sprintf(`
 		SELECT DISTINCT ON (ts)
 			ts,
 			generated_at,
@@ -437,16 +464,16 @@ func (d *DB) RainPredictionSeriesRange(ctx context.Context, site, modelName stri
 			threshold,
 			probability,
 			predict_rain,
-			rain_next_1h_mm_actual,
-			rain_next_1h_actual,
+			%s,
+			%s,
 			evaluated_at
-		FROM predictions_rain_1h
+		FROM %s
 		WHERE site = $1
 		  AND model_name = $2
 		  AND ts >= $3
 		  AND ts <= $4
 		ORDER BY ts ASC, generated_at DESC
-	`
+	`, mmCol, flagCol, table)
 
 	rows, err := d.Pool.Query(ctx, query, site, modelName, start, end)
 	if err != nil {
@@ -486,8 +513,11 @@ func (d *DB) RainPredictionSeriesRange(ctx context.Context, site, modelName stri
 		if predictRain.Valid {
 			p.PredictRain = predictRain.Bool
 		}
-		p.RainNext1hMM = nullFloatPtr(rainMM)
-		p.RainNext1hActual = nullBoolPtr(rainActual)
+		p.HorizonHours = horizonHours
+		p.RainNextMM = nullFloatPtr(rainMM)
+		p.RainNextActual = nullBoolPtr(rainActual)
+		p.RainNext1hMM = p.RainNextMM
+		p.RainNext1hActual = p.RainNextActual
 		p.EvaluatedAt = nullTimePtr(evaluatedAt)
 		points = append(points, p)
 	}
diff --git a/scripts/audit_rain_data.py b/scripts/audit_rain_data.py
index 6dd60b6..4f96541 100644
--- a/scripts/audit_rain_data.py
+++ b/scripts/audit_rain_data.py
@@ -10,6 +10,7 @@ import psycopg2
 
 from rain_model_common import (
     AVAILABLE_FEATURE_SETS,
+    DEFAULT_HORIZON_HOURS,
     RAIN_EVENT_THRESHOLD_MM,
     build_dataset,
     feature_columns_for_set,
@@ -17,8 +18,11 @@ from rain_model_common import (
     fetch_baro,
     fetch_forecast,
     fetch_ws90,
+    normalize_horizon_hours,
     model_frame,
     parse_time,
+    rain_next_flag_col,
+    rain_next_mm_col,
     to_builtin,
 )
 
@@ -29,6 +33,12 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument("--site", required=True, help="Site name (e.g. home).")
     parser.add_argument("--start", help="Start time (RFC3339 or YYYY-MM-DD).")
     parser.add_argument("--end", help="End time (RFC3339 or YYYY-MM-DD).")
+    parser.add_argument(
+        "--horizon-hours",
+        type=int,
+        default=DEFAULT_HORIZON_HOURS,
+        help="Prediction horizon in hours for target/label auditing.",
+    )
     parser.add_argument(
         "--feature-set",
         default="baseline",
@@ -57,13 +67,13 @@ def longest_zero_run(counts: np.ndarray) -> int:
     return best
 
 
-def build_weekly_balance(model_df):
+def build_weekly_balance(model_df, target_col: str):
     weekly = model_df.copy()
     iso = weekly.index.to_series().dt.isocalendar()
     weekly["year_week"] = iso["year"].astype(str) + "-W" + iso["week"].astype(str).str.zfill(2)
 
     grouped = (
-        weekly.groupby("year_week")["rain_next_1h"]
+        weekly.groupby("year_week")[target_col]
         .agg(total_rows="count", positive_rows="sum")
         .reset_index()
         .sort_values("year_week")
@@ -79,6 +89,9 @@ def main() -> int:
 
     start = parse_time(args.start) if args.start else ""
     end = parse_time(args.end) if args.end else ""
+    horizon_hours = normalize_horizon_hours(args.horizon_hours)
+    target_col = rain_next_flag_col(horizon_hours)
+    target_mm_col = rain_next_mm_col(horizon_hours)
     feature_cols = feature_columns_for_set(args.feature_set)
     needs_forecast = feature_columns_need_forecast(feature_cols)
 
@@ -89,8 +102,14 @@ def main() -> int:
         if needs_forecast:
             forecast = fetch_forecast(conn, args.site, start, end, model=args.forecast_model)
 
-    df = build_dataset(ws90, baro, forecast=forecast, rain_event_threshold_mm=RAIN_EVENT_THRESHOLD_MM)
-    model_df = model_frame(df, feature_cols, require_target=True)
+    df = build_dataset(
+        ws90,
+        baro,
+        forecast=forecast,
+        rain_event_threshold_mm=RAIN_EVENT_THRESHOLD_MM,
+        horizon_hours=horizon_hours,
+    )
+    model_df = model_frame(df, feature_cols, require_target=True, target_col=target_col)
 
     ws90_dupes = int(ws90.duplicated(subset=["ts", "station_id"]).sum()) if not ws90.empty else 0
     baro_dupes = int(baro.duplicated(subset=["ts", "source"]).sum()) if not baro.empty else 0
@@ -114,7 +133,7 @@ def main() -> int:
     baro_max_gap_min = longest_zero_run(np.array(baro_counts)) * 5 if len(baro_counts) else 0
 
     missingness = {}
-    for col in feature_cols + ["pressure_hpa", "rain_mm", "rain_inc", "rain_next_1h_mm"]:
+    for col in feature_cols + ["pressure_hpa", "rain_mm", "rain_inc", target_mm_col]:
         if col in df.columns:
             missingness[col] = float(df[col].isna().mean())
 
@@ -125,9 +144,12 @@ def main() -> int:
     report = {
         "site": args.site,
         "feature_set": args.feature_set,
+        "horizon_hours": horizon_hours,
+        "target_column": target_col,
+        "target_mm_column": target_mm_col,
         "feature_columns": feature_cols,
         "forecast_model": args.forecast_model if needs_forecast else None,
-        "target_definition": f"rain_next_1h_mm >= {RAIN_EVENT_THRESHOLD_MM:.2f}",
+        "target_definition": f"{target_mm_col} >= {RAIN_EVENT_THRESHOLD_MM:.2f}",
         "requested_window": {
             "start": start or None,
             "end": end or None,
@@ -167,8 +189,8 @@ def main() -> int:
             "max_rain_increment_5m_mm": max_rain_inc,
         },
         "class_balance": {
-            "overall_positive_rate": float(model_df["rain_next_1h"].mean()) if not model_df.empty else None,
-            "weekly": build_weekly_balance(model_df) if not model_df.empty else [],
+            "overall_positive_rate": float(model_df[target_col].mean()) if not model_df.empty else None,
+            "weekly": build_weekly_balance(model_df, target_col=target_col) if not model_df.empty else [],
         },
     }
     report = to_builtin(report)
diff --git a/scripts/check_rain_pipeline_health.py b/scripts/check_rain_pipeline_health.py
index 92186ff..3bb400e 100644
--- a/scripts/check_rain_pipeline_health.py
+++ b/scripts/check_rain_pipeline_health.py
@@ -9,6 +9,24 @@ from typing import Any
 
 import psycopg2
 
+DEFAULT_HORIZON_HOURS = 4
+
+
+def normalize_horizon_hours(horizon_hours: int) -> int:
+    out = int(horizon_hours)
+    if out <= 0:
+        raise ValueError("horizon_hours must be > 0")
+    return out
+
+
+def prediction_table_for_horizon(horizon_hours: int) -> str:
+    horizon = normalize_horizon_hours(horizon_hours)
+    if horizon == 1:
+        return "predictions_rain_1h"
+    if horizon == 4:
+        return "predictions_rain_4h"
+    raise ValueError(f"unsupported prediction-table horizon: {horizon_hours}")
+
 
 def parse_duration(value: str) -> timedelta:
     raw = value.strip().lower()
@@ -27,14 +45,20 @@ def parse_args() -> argparse.Namespace:
     parser = argparse.ArgumentParser(description="Check freshness/health of rain-model data and predictions.")
     parser.add_argument("--db-url", default=os.getenv("DATABASE_URL"), help="Postgres connection string.")
     parser.add_argument("--site", required=True, help="Site name.")
-    parser.add_argument("--model-name", default="rain_next_1h", help="Prediction model_name to check.")
+    parser.add_argument("--model-name", default="rain_next_4h", help="Prediction model_name to check.")
+    parser.add_argument(
+        "--horizon-hours",
+        type=int,
+        default=DEFAULT_HORIZON_HOURS,
+        help="Prediction horizon in hours used to select prediction storage table.",
+    )
     parser.add_argument("--max-ws90-age", default="20m", help="Max allowed age for ws90 latest row.")
     parser.add_argument("--max-baro-age", default="30m", help="Max allowed age for barometer latest row.")
     parser.add_argument("--max-forecast-age", default="3h", help="Max allowed age for forecast latest row.")
     parser.add_argument("--max-prediction-age", default="30m", help="Max allowed age for latest prediction write.")
     parser.add_argument(
         "--max-pending-eval-age",
-        default="3h",
+        default="6h",
         help="Pending evaluations older than this count toward alert.",
     )
     parser.add_argument(
@@ -91,6 +115,8 @@ def main() -> int:
     max_forecast_age = parse_duration(args.max_forecast_age)
     max_prediction_age = parse_duration(args.max_prediction_age)
     max_pending_eval_age = parse_duration(args.max_pending_eval_age)
+    horizon_hours = normalize_horizon_hours(args.horizon_hours)
+    prediction_table = prediction_table_for_horizon(horizon_hours)
 
     with psycopg2.connect(args.db_url) as conn:
         ws90_latest = fetch_latest_ts(
@@ -110,9 +136,9 @@ def main() -> int:
         )
         prediction_latest = fetch_latest_ts(
             conn,
-            """
+            f"""
             SELECT max(generated_at)
-            FROM predictions_rain_1h
+            FROM {prediction_table}
             WHERE site = %s
               AND model_name = %s
             """,
@@ -120,9 +146,9 @@ def main() -> int:
         )
         pending_eval_rows = fetch_count(
             conn,
-            """
+            f"""
             SELECT count(*)
-            FROM predictions_rain_1h
+            FROM {prediction_table}
             WHERE site = %s
               AND model_name = %s
               AND evaluated_at IS NULL
@@ -188,6 +214,8 @@ def main() -> int:
         "generated_at": now.isoformat(),
         "site": args.site,
         "model_name": args.model_name,
+        "horizon_hours": horizon_hours,
+        "prediction_table": prediction_table,
         "status": overall_status,
         "failing_checks": failing,
         "checks": checks,
diff --git a/scripts/compare_rain_reports.py b/scripts/compare_rain_reports.py
new file mode 100644
index 0000000..712486b
--- /dev/null
+++ b/scripts/compare_rain_reports.py
@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+
+import argparse
+import json
+from pathlib import Path
+from typing import Any
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(description="Compare two rain-model training reports.")
+    parser.add_argument("--baseline", required=True, help="Baseline report path (for example 1h).")
+    parser.add_argument("--candidate", required=True, help="Candidate report path (for example 4h).")
+    return parser.parse_args()
+
+
+def load_json(path: str) -> dict[str, Any]:
+    p = Path(path)
+    with p.open("r", encoding="utf-8") as f:
+        return json.load(f)
+
+
+def to_float(v: Any) -> float | None:
+    if v is None:
+        return None
+    try:
+        return float(v)
+    except (TypeError, ValueError):
+        return None
+
+
+def metric(report: dict[str, Any], split: str, key: str) -> float | None:
+    return to_float(report.get(split, {}).get(key))
+
+
+def delta_str(base: float | None, cand: float | None) -> str:
+    if base is None or cand is None:
+        return "n/a"
+    d = cand - base
+    return f"{d:+.4f}"
+
+
+def main() -> int:
+    args = parse_args()
+    baseline = load_json(args.baseline)
+    candidate = load_json(args.candidate)
+
+    pairs = [
+        ("precision", metric(baseline, "test_metrics", "precision"), metric(candidate, "test_metrics", "precision")),
+        ("recall", metric(baseline, "test_metrics", "recall"), metric(candidate, "test_metrics", "recall")),
+        ("f1", metric(baseline, "test_metrics", "f1"), metric(candidate, "test_metrics", "f1")),
+        ("pr_auc", metric(baseline, "test_metrics", "pr_auc"), metric(candidate, "test_metrics", "pr_auc")),
+        ("roc_auc", metric(baseline, "test_metrics", "roc_auc"), metric(candidate, "test_metrics", "roc_auc")),
+        ("brier", metric(baseline, "test_metrics", "brier"), metric(candidate, "test_metrics", "brier")),
+    ]
+
+    print("Rain report comparison:")
+    print(
+        f"  baseline: version={baseline.get('model_version')} "
+        f"horizon={baseline.get('horizon_hours')}h "
+        f"target={baseline.get('target_definition')}"
+    )
+    print(
+        f"  candidate: version={candidate.get('model_version')} "
+        f"horizon={candidate.get('horizon_hours')}h "
+        f"target={candidate.get('target_definition')}"
+    )
+    print("  metrics (candidate - baseline):")
+    for name, base, cand in pairs:
+        base_txt = "n/a" if base is None else f"{base:.4f}"
+        cand_txt = "n/a" if cand is None else f"{cand:.4f}"
+        print(f"    {name}: baseline={base_txt} candidate={cand_txt} delta={delta_str(base, cand)}")
+
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/scripts/predict_rain_model.py b/scripts/predict_rain_model.py
index 9d81cb2..571bb62 100644
--- a/scripts/predict_rain_model.py
+++ b/scripts/predict_rain_model.py
@@ -9,13 +9,18 @@ import psycopg2
 from psycopg2.extras import Json
 
 from rain_model_common import (
+    DEFAULT_HORIZON_HOURS,
     build_dataset,
     feature_columns_need_forecast,
     fetch_baro,
     fetch_forecast,
     fetch_ws90,
     model_frame,
+    normalize_horizon_hours,
     parse_time,
+    prediction_table_for_horizon,
+    rain_next_flag_col,
+    rain_next_mm_col,
     to_builtin,
 )
 
@@ -30,8 +35,13 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument("--db-url", default=os.getenv("DATABASE_URL"), help="Postgres connection string.")
     parser.add_argument("--site", required=True, help="Site name (e.g. home).")
     parser.add_argument("--model-path", default="models/rain_model.pkl", help="Path to trained model artifact.")
-    parser.add_argument("--model-name", default="rain_next_1h", help="Logical prediction model name.")
+    parser.add_argument("--model-name", default="rain_next_4h", help="Logical prediction model name.")
     parser.add_argument("--model-version", help="Override artifact model_version.")
+    parser.add_argument(
+        "--horizon-hours",
+        type=int,
+        help="Prediction horizon in hours. Defaults to artifact horizon when present, else 4.",
+    )
     parser.add_argument(
         "--at",
         help="Prediction timestamp (RFC3339 or YYYY-MM-DD). Default: current UTC time.",
@@ -98,9 +108,21 @@ def main() -> int:
     threshold = float(artifact.get("threshold", 0.5))
     model_version = args.model_version or artifact.get("model_version") or "unknown"
     forecast_model = str(artifact.get("forecast_model") or args.forecast_model)
+    artifact_horizon = artifact.get("horizon_hours")
+    if args.horizon_hours is not None:
+        horizon_hours = normalize_horizon_hours(args.horizon_hours)
+    elif artifact_horizon is not None:
+        horizon_hours = normalize_horizon_hours(int(artifact_horizon))
+    else:
+        horizon_hours = DEFAULT_HORIZON_HOURS
+    target_col = str(artifact.get("target_col") or rain_next_flag_col(horizon_hours))
+    target_mm_col = str(artifact.get("target_mm_col") or rain_next_mm_col(horizon_hours))
+    prediction_table = prediction_table_for_horizon(horizon_hours)
+    actual_mm_col = f"{target_mm_col}_actual"
+    actual_flag_col = f"{target_col}_actual"
 
     fetch_start = (at - timedelta(hours=args.history_hours)).isoformat()
-    fetch_end = (at + timedelta(hours=1, minutes=5)).isoformat()
+    fetch_end = (at + timedelta(hours=horizon_hours, minutes=5)).isoformat()
 
     with psycopg2.connect(args.db_url) as conn:
         ws90 = fetch_ws90(conn, args.site, fetch_start, fetch_end)
@@ -122,7 +144,7 @@ def main() -> int:
                 return 0
             raise RuntimeError(message)
 
-        full_df = build_dataset(ws90, baro, forecast=forecast)
+        full_df = build_dataset(ws90, baro, forecast=forecast, horizon_hours=horizon_hours)
         feature_df = model_frame(full_df, feature_cols=features, require_target=False)
         candidates = feature_df.loc[feature_df.index <= at]
         if candidates.empty:
@@ -143,9 +165,9 @@ def main() -> int:
         actual_flag = None
         evaluated_at = None
         latest_available = full_df.index.max().to_pydatetime()
-        if pred_ts + timedelta(hours=1) <= latest_available:
-            next_mm = full_df.loc[pred_ts, "rain_next_1h_mm"]
-            next_flag = full_df.loc[pred_ts, "rain_next_1h"]
+        if pred_ts + timedelta(hours=horizon_hours) <= latest_available:
+            next_mm = full_df.loc[pred_ts, target_mm_col]
+            next_flag = full_df.loc[pred_ts, target_col]
             if next_mm == next_mm:  # NaN-safe check
                 actual_mm = float(next_mm)
             if next_flag == next_flag:
@@ -156,6 +178,10 @@ def main() -> int:
             "artifact_path": args.model_path,
             "artifact_model_version": artifact.get("model_version"),
             "artifact_feature_set": feature_set,
+            "horizon_hours": horizon_hours,
+            "target_col": target_col,
+            "target_mm_col": target_mm_col,
+            "prediction_table": prediction_table,
             "forecast_model": forecast_model if needs_forecast else None,
             "needs_forecast_features": needs_forecast,
             "feature_values": {col: float(row.iloc[0][col]) for col in features},
@@ -170,6 +196,7 @@ def main() -> int:
         print(f"  site: {args.site}")
         print(f"  model_name: {args.model_name}")
         print(f"  model_version: {model_version}")
+        print(f"  horizon_hours: {horizon_hours}")
         if feature_set:
             print(f"  feature_set: {feature_set}")
         print(f"  pred_ts: {pred_ts.isoformat()}")
@@ -182,10 +209,8 @@ def main() -> int:
             print("dry-run enabled; skipping DB upsert.")
             return 0
 
-        with conn.cursor() as cur:
-            cur.execute(
-                """
-                INSERT INTO predictions_rain_1h (
+        query = f"""
+                INSERT INTO {prediction_table} (
                     ts,
                     generated_at,
                     site,
@@ -194,8 +219,8 @@ def main() -> int:
                     threshold,
                     probability,
                     predict_rain,
-                    rain_next_1h_mm_actual,
-                    rain_next_1h_actual,
+                    {actual_mm_col},
+                    {actual_flag_col},
                     evaluated_at,
                     metadata
                 ) VALUES (
@@ -207,11 +232,14 @@ def main() -> int:
                     threshold = EXCLUDED.threshold,
                     probability = EXCLUDED.probability,
                     predict_rain = EXCLUDED.predict_rain,
-                    rain_next_1h_mm_actual = COALESCE(EXCLUDED.rain_next_1h_mm_actual, predictions_rain_1h.rain_next_1h_mm_actual),
-                    rain_next_1h_actual = COALESCE(EXCLUDED.rain_next_1h_actual, predictions_rain_1h.rain_next_1h_actual),
-                    evaluated_at = COALESCE(EXCLUDED.evaluated_at, predictions_rain_1h.evaluated_at),
+                    {actual_mm_col} = COALESCE(EXCLUDED.{actual_mm_col}, {prediction_table}.{actual_mm_col}),
+                    {actual_flag_col} = COALESCE(EXCLUDED.{actual_flag_col}, {prediction_table}.{actual_flag_col}),
+                    evaluated_at = COALESCE(EXCLUDED.evaluated_at, {prediction_table}.evaluated_at),
                     metadata = EXCLUDED.metadata
-                """,
+                """
+        with conn.cursor() as cur:
+            cur.execute(
+                query,
                 (
                     pred_ts,
                     args.site,
@@ -227,7 +255,7 @@ def main() -> int:
                 ),
             )
             conn.commit()
-        print("Prediction upserted into predictions_rain_1h.")
+        print(f"Prediction upserted into {prediction_table}.")
 
     return 0
 
diff --git a/scripts/rain_model_common.py b/scripts/rain_model_common.py
index 86b1b12..997607a 100644
--- a/scripts/rain_model_common.py
+++ b/scripts/rain_model_common.py
@@ -86,7 +86,46 @@ FEATURE_COLUMNS = BASELINE_FEATURE_COLUMNS
 
 RAIN_EVENT_THRESHOLD_MM = 0.2
 RAIN_SPIKE_THRESHOLD_MM_5M = 5.0
-RAIN_HORIZON_BUCKETS = 12  # 12 * 5m = 1h
+BUCKET_MINUTES = 5
+DEFAULT_HORIZON_HOURS = 4
+SUPPORTED_PREDICTION_HORIZONS = (1, 4)
+
+
+def normalize_horizon_hours(horizon_hours: int) -> int:
+    out = int(horizon_hours)
+    if out <= 0:
+        raise ValueError("horizon_hours must be > 0")
+    return out
+
+
+def horizon_suffix(horizon_hours: int) -> str:
+    return f"{normalize_horizon_hours(horizon_hours)}h"
+
+
+def horizon_buckets(horizon_hours: int) -> int:
+    hours = normalize_horizon_hours(horizon_hours)
+    return (hours * 60) // BUCKET_MINUTES
+
+
+def rain_last_mm_col(horizon_hours: int) -> str:
+    return f"rain_last_{horizon_suffix(horizon_hours)}_mm"
+
+
+def rain_next_mm_col(horizon_hours: int) -> str:
+    return f"rain_next_{horizon_suffix(horizon_hours)}_mm"
+
+
+def rain_next_flag_col(horizon_hours: int) -> str:
+    return f"rain_next_{horizon_suffix(horizon_hours)}"
+
+
+def prediction_table_for_horizon(horizon_hours: int) -> str:
+    horizon = normalize_horizon_hours(horizon_hours)
+    if horizon == 1:
+        return "predictions_rain_1h"
+    if horizon == 4:
+        return "predictions_rain_4h"
+    raise ValueError(f"unsupported prediction-table horizon: {horizon_hours}")
 
 
 def parse_time(value: str) -> str:
@@ -232,6 +271,7 @@ def build_dataset(
     baro: pd.DataFrame,
     forecast: pd.DataFrame | None = None,
     rain_event_threshold_mm: float = RAIN_EVENT_THRESHOLD_MM,
+    horizon_hours: int = 1,
 ) -> pd.DataFrame:
     if ws90.empty:
         raise RuntimeError("no ws90 observations found")
@@ -261,12 +301,20 @@ def build_dataset(
     df["rain_inc"] = df["rain_inc_raw"].clip(lower=0)
     df["rain_spike_5m"] = df["rain_inc"] >= RAIN_SPIKE_THRESHOLD_MM_5M
 
-    window = RAIN_HORIZON_BUCKETS
-    df["rain_last_1h_mm"] = df["rain_inc"].rolling(window=window, min_periods=1).sum()
-    df["rain_next_1h_mm"] = df["rain_inc"].rolling(window=window, min_periods=1).sum().shift(-(window - 1))
-    df["rain_next_1h"] = df["rain_next_1h_mm"] >= rain_event_threshold_mm
+    windows: dict[int, int] = {
+        1: horizon_buckets(1),
+        normalize_horizon_hours(horizon_hours): horizon_buckets(horizon_hours),
+    }
+    for hours, window in windows.items():
+        rain_last_col = rain_last_mm_col(hours)
+        rain_next_mm = rain_next_mm_col(hours)
+        rain_next_flag = rain_next_flag_col(hours)
+        df[rain_last_col] = df["rain_inc"].rolling(window=window, min_periods=1).sum()
+        df[rain_next_mm] = df["rain_inc"].rolling(window=window, min_periods=1).sum().shift(-(window - 1))
+        df[rain_next_flag] = df[rain_next_mm] >= rain_event_threshold_mm
 
-    df["pressure_trend_1h"] = df["pressure_hpa"] - df["pressure_hpa"].shift(window)
+    window_1h = horizon_buckets(1)
+    df["pressure_trend_1h"] = df["pressure_hpa"] - df["pressure_hpa"].shift(window_1h)
 
     # Wind direction cyclical encoding.
     radians = np.deg2rad(df["wind_dir_deg"] % 360.0)
@@ -279,14 +327,14 @@ def build_dataset(
     df["wind_avg_lag_5m"] = df["wind_avg_m_s"].shift(1)
     df["pressure_lag_5m"] = df["pressure_hpa"].shift(1)
 
-    df["temp_roll_1h_mean"] = df["temperature_c"].rolling(window=window, min_periods=3).mean()
-    df["temp_roll_1h_std"] = df["temperature_c"].rolling(window=window, min_periods=3).std()
-    df["humidity_roll_1h_mean"] = df["humidity"].rolling(window=window, min_periods=3).mean()
-    df["humidity_roll_1h_std"] = df["humidity"].rolling(window=window, min_periods=3).std()
-    df["wind_avg_roll_1h_mean"] = df["wind_avg_m_s"].rolling(window=window, min_periods=3).mean()
-    df["wind_gust_roll_1h_max"] = df["wind_max_m_s"].rolling(window=window, min_periods=3).max()
-    df["pressure_roll_1h_mean"] = df["pressure_hpa"].rolling(window=window, min_periods=3).mean()
-    df["pressure_roll_1h_std"] = df["pressure_hpa"].rolling(window=window, min_periods=3).std()
+    df["temp_roll_1h_mean"] = df["temperature_c"].rolling(window=window_1h, min_periods=3).mean()
+    df["temp_roll_1h_std"] = df["temperature_c"].rolling(window=window_1h, min_periods=3).std()
+    df["humidity_roll_1h_mean"] = df["humidity"].rolling(window=window_1h, min_periods=3).mean()
+    df["humidity_roll_1h_std"] = df["humidity"].rolling(window=window_1h, min_periods=3).std()
+    df["wind_avg_roll_1h_mean"] = df["wind_avg_m_s"].rolling(window=window_1h, min_periods=3).mean()
+    df["wind_gust_roll_1h_max"] = df["wind_max_m_s"].rolling(window=window_1h, min_periods=3).max()
+    df["pressure_roll_1h_mean"] = df["pressure_hpa"].rolling(window=window_1h, min_periods=3).mean()
+    df["pressure_roll_1h_std"] = df["pressure_hpa"].rolling(window=window_1h, min_periods=3).std()
 
     # Calendar/seasonality features (UTC based).
     hour_of_day = df.index.hour + (df.index.minute / 60.0)
@@ -304,11 +352,16 @@ def build_dataset(
     return df
 
 
-def model_frame(df: pd.DataFrame, feature_cols: list[str] | None = None, require_target: bool = True) -> pd.DataFrame:
+def model_frame(
+    df: pd.DataFrame,
+    feature_cols: list[str] | None = None,
+    require_target: bool = True,
+    target_col: str | None = None,
+) -> pd.DataFrame:
     features = feature_cols or FEATURE_COLUMNS
     required = list(features)
     if require_target:
-        required.append("rain_next_1h")
+        required.append(target_col or rain_next_flag_col(1))
     out = df.dropna(subset=required).copy()
     return out.sort_index()
 
diff --git a/scripts/run_p0_rain_workflow.sh b/scripts/run_p0_rain_workflow.sh
index 478fd6a..3f06201 100644
--- a/scripts/run_p0_rain_workflow.sh
+++ b/scripts/run_p0_rain_workflow.sh
@@ -4,7 +4,9 @@ set -euo pipefail
 SITE="${SITE:-home}"
 START="${START:-2026-02-01T00:00:00Z}"
 END="${END:-2026-03-03T23:55:00Z}"
-MODEL_VERSION="${MODEL_VERSION:-rain-logreg-v1}"
+HORIZON_HOURS="${HORIZON_HOURS:-4}"
+MODEL_NAME="${MODEL_NAME:-rain_next_${HORIZON_HOURS}h}"
+MODEL_VERSION="${MODEL_VERSION:-rain-logreg-v2-${HORIZON_HOURS}h}"
 MODEL_PATH="${MODEL_PATH:-models/rain_model.pkl}"
 REPORT_PATH="${REPORT_PATH:-models/rain_model_report.json}"
 AUDIT_PATH="${AUDIT_PATH:-models/rain_data_audit.json}"
@@ -24,6 +26,7 @@ python scripts/audit_rain_data.py \
   --site "$SITE" \
   --start "$START" \
   --end "$END" \
+  --horizon-hours "$HORIZON_HOURS" \
   --feature-set "$FEATURE_SET" \
   --forecast-model "$FORECAST_MODEL" \
   --out "$AUDIT_PATH"
@@ -33,6 +36,7 @@ python scripts/train_rain_model.py \
   --site "$SITE" \
   --start "$START" \
   --end "$END" \
+  --horizon-hours "$HORIZON_HOURS" \
   --train-ratio 0.7 \
   --val-ratio 0.15 \
   --min-precision 0.70 \
@@ -50,7 +54,8 @@ echo "Writing current prediction..."
 python scripts/predict_rain_model.py \
   --site "$SITE" \
   --model-path "$MODEL_PATH" \
-  --model-name "rain_next_1h" \
+  --model-name "$MODEL_NAME" \
+  --horizon-hours "$HORIZON_HOURS" \
   --forecast-model "$FORECAST_MODEL"
 
 echo "P0 rain workflow complete."
diff --git a/scripts/run_rain_ml_worker.py b/scripts/run_rain_ml_worker.py
index 7ce231b..8865054 100644
--- a/scripts/run_rain_ml_worker.py
+++ b/scripts/run_rain_ml_worker.py
@@ -40,6 +40,7 @@ def read_env_bool(name: str, default: bool) -> bool:
 class WorkerConfig:
     database_url: str
     site: str
+    horizon_hours: int
     model_name: str
     model_version_base: str
     model_family: str
@@ -166,6 +167,8 @@ def run_training_cycle(cfg: WorkerConfig, env: dict[str, str]) -> None:
             start,
             "--end",
             end,
+            "--horizon-hours",
+            str(cfg.horizon_hours),
             "--feature-set",
             cfg.feature_set,
             "--forecast-model",
@@ -185,6 +188,8 @@ def run_training_cycle(cfg: WorkerConfig, env: dict[str, str]) -> None:
         start,
         "--end",
         end,
+        "--horizon-hours",
+        str(cfg.horizon_hours),
         "--train-ratio",
         str(cfg.train_ratio),
         "--val-ratio",
@@ -269,6 +274,8 @@ def run_predict_once(cfg: WorkerConfig, env: dict[str, str]) -> None:
             str(cfg.model_path),
             "--model-name",
             cfg.model_name,
+            "--horizon-hours",
+            str(cfg.horizon_hours),
             "--forecast-model",
             cfg.forecast_model,
             *(["--allow-empty"] if cfg.allow_empty_data else ["--strict-source-data"]),
@@ -289,8 +296,9 @@ def load_config() -> WorkerConfig:
     return WorkerConfig(
         database_url=database_url,
         site=read_env("RAIN_SITE", "home"),
-        model_name=read_env("RAIN_MODEL_NAME", "rain_next_1h"),
-        model_version_base=read_env("RAIN_MODEL_VERSION_BASE", "rain-auto-v1-extended"),
+        horizon_hours=read_env_int("RAIN_HORIZON_HOURS", 4),
+        model_name=read_env("RAIN_MODEL_NAME", "rain_next_4h"),
+        model_version_base=read_env("RAIN_MODEL_VERSION_BASE", "rain-auto-v2-extended-4h"),
         model_family=read_env("RAIN_MODEL_FAMILY", "auto"),
         feature_set=read_env("RAIN_FEATURE_SET", "extended"),
         forecast_model=read_env("RAIN_FORECAST_MODEL", "ecmwf"),
@@ -338,6 +346,7 @@ def main() -> int:
     print(
         "[rain-ml] worker start "
         f"site={cfg.site} "
+        f"horizon_hours={cfg.horizon_hours} "
         f"model_name={cfg.model_name} "
         f"model_family={cfg.model_family} "
         f"feature_set={cfg.feature_set} "
diff --git a/scripts/train_rain_model.py b/scripts/train_rain_model.py
index 96e2d53..4662f1b 100644
--- a/scripts/train_rain_model.py
+++ b/scripts/train_rain_model.py
@@ -20,6 +20,7 @@ from sklearn.preprocessing import StandardScaler
 
 from rain_model_common import (
     AVAILABLE_FEATURE_SETS,
+    DEFAULT_HORIZON_HOURS,
     RAIN_EVENT_THRESHOLD_MM,
     build_dataset,
     evaluate_probs,
@@ -28,8 +29,13 @@ from rain_model_common import (
     fetch_ws90,
     feature_columns_for_set,
     feature_columns_need_forecast,
+    horizon_suffix,
     model_frame,
+    normalize_horizon_hours,
     parse_time,
+    rain_last_mm_col,
+    rain_next_flag_col,
+    rain_next_mm_col,
     safe_pr_auc,
     safe_roc_auc,
     select_threshold,
@@ -49,11 +55,17 @@ THRESHOLD_POLICIES = ("validation", "walk_forward")
 
 
 def parse_args() -> argparse.Namespace:
-    parser = argparse.ArgumentParser(description="Train a rain prediction model (next 1h >= 0.2mm).")
+    parser = argparse.ArgumentParser(description="Train a rain prediction model (next Nh >= threshold).")
     parser.add_argument("--db-url", default=os.getenv("DATABASE_URL"), help="Postgres connection string.")
     parser.add_argument("--site", required=True, help="Site name (e.g. home).")
     parser.add_argument("--start", help="Start time (RFC3339 or YYYY-MM-DD).")
     parser.add_argument("--end", help="End time (RFC3339 or YYYY-MM-DD).")
+    parser.add_argument(
+        "--horizon-hours",
+        type=int,
+        default=DEFAULT_HORIZON_HOURS,
+        help="Prediction horizon in hours (for example 1 or 4).",
+    )
     parser.add_argument("--train-ratio", type=float, default=0.7, help="Time-ordered train split ratio.")
     parser.add_argument("--val-ratio", type=float, default=0.15, help="Time-ordered validation split ratio.")
     parser.add_argument(
@@ -464,14 +476,18 @@ def evaluate_calibration_methods(
     return selected, results
 
 
-def evaluate_naive_baselines(test_df, y_test: np.ndarray) -> dict[str, Any]:
+def evaluate_naive_baselines(
+    test_df,
+    y_test: np.ndarray,
+    persistence_context_col: str,
+) -> dict[str, Any]:
     out: dict[str, Any] = {}
 
-    if "rain_last_1h_mm" in test_df.columns:
-        rain_last = test_df["rain_last_1h_mm"].to_numpy(dtype=float)
+    if persistence_context_col in test_df.columns:
+        rain_last = test_df[persistence_context_col].to_numpy(dtype=float)
         persistence_prob = (rain_last >= RAIN_EVENT_THRESHOLD_MM).astype(float)
-        out["persistence_last_1h"] = {
-            "rule": f"predict rain when rain_last_1h_mm >= {RAIN_EVENT_THRESHOLD_MM:.2f}",
+        out[f"persistence_{persistence_context_col}"] = {
+            "rule": f"predict rain when {persistence_context_col} >= {RAIN_EVENT_THRESHOLD_MM:.2f}",
             "metrics": evaluate_probs(y_true=y_test, y_prob=persistence_prob, threshold=0.5),
         }
 
@@ -512,6 +528,8 @@ def evaluate_sliced_performance(
     y_true: np.ndarray,
     y_prob: np.ndarray,
     threshold: float,
+    context_col: str,
+    context_label: str,
     min_rows_per_slice: int = 30,
 ) -> dict[str, Any]:
     frame = pd.DataFrame(
@@ -530,7 +548,11 @@ def evaluate_sliced_performance(
     weekly_positive_rate = frame.groupby(week_label)["y_true"].transform("mean")
     rainy_week = weekly_positive_rate >= overall_rate
 
-    rain_context = test_df["rain_last_1h_mm"].to_numpy(dtype=float) if "rain_last_1h_mm" in test_df.columns else np.zeros(len(test_df))
+    rain_context = (
+        test_df[context_col].to_numpy(dtype=float)
+        if context_col in test_df.columns
+        else np.zeros(len(test_df))
+    )
     wet_context = rain_context >= RAIN_EVENT_THRESHOLD_MM
 
     wind_values = test_df["wind_max_m_s"].to_numpy(dtype=float) if "wind_max_m_s" in test_df.columns else np.full(len(test_df), np.nan)
@@ -545,8 +567,8 @@ def evaluate_sliced_performance(
         ("nighttime_utc", np.asarray(~is_day, dtype=bool), "18:00-05:59 UTC"),
         ("rainy_weeks", np.asarray(rainy_week, dtype=bool), "weeks with positive-rate >= test positive-rate"),
         ("non_rainy_weeks", np.asarray(~rainy_week, dtype=bool), "weeks with positive-rate < test positive-rate"),
-        ("wet_context_last_1h", np.asarray(wet_context, dtype=bool), f"rain_last_1h_mm >= {RAIN_EVENT_THRESHOLD_MM:.2f}"),
-        ("dry_context_last_1h", np.asarray(~wet_context, dtype=bool), f"rain_last_1h_mm < {RAIN_EVENT_THRESHOLD_MM:.2f}"),
+        ("wet_context_recent_rain", np.asarray(wet_context, dtype=bool), f"{context_label} >= {RAIN_EVENT_THRESHOLD_MM:.2f}"),
+        ("dry_context_recent_rain", np.asarray(~wet_context, dtype=bool), f"{context_label} < {RAIN_EVENT_THRESHOLD_MM:.2f}"),
         ("windy_q75", np.asarray(windy, dtype=bool), "wind_max_m_s >= test 75th percentile"),
         ("calm_below_q75", np.asarray(~windy, dtype=bool), "wind_max_m_s < test 75th percentile"),
     ]
@@ -585,6 +607,7 @@ def evaluate_sliced_performance(
 def tune_threshold_walk_forward(
     model_df,
     feature_cols: list[str],
+    target_col: str,
     model_family: str,
     model_params: dict[str, Any],
     calibration_method: str,
@@ -627,8 +650,8 @@ def tune_threshold_walk_forward(
         if len(fold_train) < 160 or len(fold_test) < 25:
             continue
 
-        y_fold_train = fold_train["rain_next_1h"].astype(int).to_numpy()
-        y_fold_test = fold_test["rain_next_1h"].astype(int).to_numpy()
+        y_fold_train = fold_train[target_col].astype(int).to_numpy()
+        y_fold_test = fold_test[target_col].astype(int).to_numpy()
         if len(np.unique(y_fold_train)) < 2:
             continue
 
@@ -706,6 +729,7 @@ def tune_threshold_walk_forward(
 def walk_forward_backtest(
     model_df,
     feature_cols: list[str],
+    target_col: str,
     model_family: str,
     model_params: dict[str, Any],
     calibration_method: str,
@@ -745,8 +769,8 @@ def walk_forward_backtest(
         if len(fold_train) < 160 or len(fold_test) < 25:
             continue
 
-        y_fold_train = fold_train["rain_next_1h"].astype(int).to_numpy()
-        y_fold_test = fold_test["rain_next_1h"].astype(int).to_numpy()
+        y_fold_train = fold_train[target_col].astype(int).to_numpy()
+        y_fold_test = fold_test[target_col].astype(int).to_numpy()
         if len(np.unique(y_fold_train)) < 2:
             continue
 
@@ -755,8 +779,8 @@ def walk_forward_backtest(
             continue
         inner_train = fold_train.iloc[:-inner_val_rows]
         inner_val = fold_train.iloc[-inner_val_rows:]
-        y_inner_train = inner_train["rain_next_1h"].astype(int).to_numpy()
-        y_inner_val = inner_val["rain_next_1h"].astype(int).to_numpy()
+        y_inner_train = inner_train[target_col].astype(int).to_numpy()
+        y_inner_val = inner_val[target_col].astype(int).to_numpy()
         if len(np.unique(y_inner_train)) < 2:
             continue
 
@@ -987,6 +1011,11 @@ def main() -> int:
 
     start = parse_time(args.start) if args.start else ""
     end = parse_time(args.end) if args.end else ""
+    horizon_hours = normalize_horizon_hours(args.horizon_hours)
+    horizon_label = horizon_suffix(horizon_hours)
+    target_col = rain_next_flag_col(horizon_hours)
+    target_mm_col = rain_next_mm_col(horizon_hours)
+    persistence_context_col = rain_last_mm_col(horizon_hours)
     feature_cols = feature_columns_for_set(args.feature_set)
     needs_forecast = feature_columns_need_forecast(feature_cols)
     calibration_methods = parse_calibration_methods(args.calibration_methods)
@@ -1011,8 +1040,21 @@ def main() -> int:
             return 0
         raise RuntimeError(message)
 
-    full_df = build_dataset(ws90, baro, forecast=forecast, rain_event_threshold_mm=RAIN_EVENT_THRESHOLD_MM)
-    model_df = model_frame(full_df, feature_cols, require_target=True)
+    full_df = build_dataset(
+        ws90,
+        baro,
+        forecast=forecast,
+        rain_event_threshold_mm=RAIN_EVENT_THRESHOLD_MM,
+        horizon_hours=horizon_hours,
+    )
+    if persistence_context_col not in full_df.columns:
+        persistence_context_col = rain_last_mm_col(1)
+    model_df = model_frame(
+        full_df,
+        feature_cols,
+        require_target=True,
+        target_col=target_col,
+    )
     if len(model_df) < args.min_rows:
         message = f"not enough model-ready rows after filtering (need >= {args.min_rows})"
         if args.allow_empty:
@@ -1027,11 +1069,11 @@ def main() -> int:
     )
 
     x_train = train_df[feature_cols]
-    y_train = train_df["rain_next_1h"].astype(int).to_numpy()
+    y_train = train_df[target_col].astype(int).to_numpy()
     x_val = val_df[feature_cols]
-    y_val = val_df["rain_next_1h"].astype(int).to_numpy()
+    y_val = val_df[target_col].astype(int).to_numpy()
     x_test = test_df[feature_cols]
-    y_test = test_df["rain_next_1h"].astype(int).to_numpy()
+    y_test = test_df[target_col].astype(int).to_numpy()
 
     if len(np.unique(y_train)) < 2:
         raise RuntimeError("training split does not contain both classes; cannot train classifier")
@@ -1073,6 +1115,7 @@ def main() -> int:
         threshold_tuning_walk_forward = tune_threshold_walk_forward(
             model_df=model_df.iloc[: len(train_df) + len(val_df)],
             feature_cols=feature_cols,
+            target_col=target_col,
             model_family=selected_model_family,
             model_params=selected_model_params,
             calibration_method=selected_calibration_method,
@@ -1093,7 +1136,7 @@ def main() -> int:
 
     train_val_df = model_df.iloc[: len(train_df) + len(val_df)]
     x_train_val = train_val_df[feature_cols]
-    y_train_val = train_val_df["rain_next_1h"].astype(int).to_numpy()
+    y_train_val = train_val_df[target_col].astype(int).to_numpy()
 
     final_model, final_fit_info = fit_with_optional_calibration(
         model_family=selected_model_family,
@@ -1109,16 +1152,23 @@ def main() -> int:
     test_calibration = {
         "ece_10": expected_calibration_error(y_true=y_test, y_prob=y_test_prob, bins=10),
     }
-    naive_baselines_test = evaluate_naive_baselines(test_df=test_df, y_test=y_test)
+    naive_baselines_test = evaluate_naive_baselines(
+        test_df=test_df,
+        y_test=y_test,
+        persistence_context_col=persistence_context_col,
+    )
     sliced_performance = evaluate_sliced_performance(
         test_df=test_df,
         y_true=y_test,
         y_prob=y_test_prob,
         threshold=chosen_threshold,
+        context_col=persistence_context_col,
+        context_label=persistence_context_col,
     )
     walk_forward = walk_forward_backtest(
         model_df=model_df,
         feature_cols=feature_cols,
+        target_col=target_col,
         model_family=selected_model_family,
         model_params=selected_model_params,
         calibration_method=selected_calibration_method,
@@ -1135,8 +1185,12 @@ def main() -> int:
         "model_family_requested": args.model_family,
         "model_family": selected_model_family,
         "model_params": selected_model_params,
+        "horizon_hours": horizon_hours,
+        "horizon_label": horizon_label,
         "feature_set": args.feature_set,
-        "target_definition": f"rain_next_1h_mm >= {RAIN_EVENT_THRESHOLD_MM:.2f}",
+        "target_column": target_col,
+        "target_mm_column": target_mm_col,
+        "target_definition": f"{target_mm_col} >= {RAIN_EVENT_THRESHOLD_MM:.2f}",
         "feature_columns": feature_cols,
         "forecast_model": args.forecast_model if needs_forecast else None,
         "calibration_method_requested": calibration_methods,
@@ -1207,6 +1261,7 @@ def main() -> int:
     print(f"  site: {args.site}")
     print(f"  model_version: {args.model_version}")
     print(f"  model_family: {selected_model_family} (requested={args.model_family})")
+    print(f"  horizon: {horizon_hours}h")
     print(f"  model_params: {selected_model_params}")
     print(f"  calibration_method: {report['calibration_method']}")
     print(
@@ -1298,7 +1353,7 @@ def main() -> int:
         dataset_dir = os.path.dirname(dataset_out)
         if dataset_dir:
             os.makedirs(dataset_dir, exist_ok=True)
-        snapshot_cols = list(dict.fromkeys(feature_cols + ["rain_next_1h", "rain_next_1h_mm"]))
+        snapshot_cols = list(dict.fromkeys(feature_cols + [target_col, target_mm_col]))
         model_df[snapshot_cols].to_csv(dataset_out, index=True, index_label="ts")
         print(f"Saved dataset snapshot to {dataset_out}")
 
@@ -1320,6 +1375,10 @@ def main() -> int:
                 "forecast_model": args.forecast_model if needs_forecast else None,
                 "threshold": float(chosen_threshold),
                 "target_mm": float(RAIN_EVENT_THRESHOLD_MM),
+                "horizon_hours": horizon_hours,
+                "target_col": target_col,
+                "target_mm_col": target_mm_col,
+                "persistence_context_col": persistence_context_col,
                 "model_version": args.model_version,
                 "trained_at": datetime.now(timezone.utc).isoformat(),
                 "split": report["split"],
diff --git a/todo.md b/todo.md
index 894bf38..43111e6 100644
--- a/todo.md
+++ b/todo.md
@@ -55,3 +55,25 @@ Priority key: `P0` = critical/blocking, `P1` = important, `P2` = later optimizat
 - [x] [P0] Train baseline model on full available history and capture metrics. (completed on runtime machine)
 - [x] [P1] Add one expanded feature set and rerun evaluation. (completed on runtime machine 2026-03-12 with `feature_set=extended`, `model_version=rain-auto-v1-extended-202603120932`)
 - [x] [P0] Decide v1 threshold and define deployment interface.
+
+## 9) Extension Plan: 4-Hour Precipitation Window (Not Started)
+- [x] [P0] Lock v2 target definition for horizon extension: `rain_next_4h_mm >= <threshold_mm>` and explicitly decide whether the threshold remains `0.2mm` or is increased for 4-hour labeling. (implemented with `0.2mm` carry-forward)
+- [x] [P0] Decide rollout strategy: additive dual-horizon support (`1h` + `4h`) vs direct replacement; prefer dual-horizon for safe cutover. (implemented as additive dual-horizon)
+- [x] [P0] Parameterize label horizon in shared ML code (`scripts/rain_model_common.py`) so target columns are generated for 4-hour windows (48 x 5-minute buckets) instead of hard-coded 1-hour columns.
+- [x] [P1] Revisit persistence/context features currently tied to `rain_last_1h_mm`; decide whether to keep 1-hour context, add 4-hour context, or both for the 4-hour target. (implemented horizon-aware context column selection)
+- [x] [P0] Update training pipeline (`scripts/train_rain_model.py`) to train against the 4-hour target column, including reports, model-card content, dataset snapshot columns, and artifact metadata.
+- [x] [P0] Update audit pipeline (`scripts/audit_rain_data.py`) to report class balance and target definition for 4-hour labels.
+- [x] [P0] Update inference pipeline (`scripts/predict_rain_model.py`) to use the 4-hour target, including realized-outcome availability checks (`pred_ts + 4h`) and metadata/reporting fields.
+- [x] [P0] Finalize DB storage design for 4-hour predictions (new `predictions_rain_4h` table vs generic horizon column strategy) before migrations. (implemented dedicated `predictions_rain_4h` table)
+- [x] [P0] Create schema migration (recommended: new hypertable `predictions_rain_4h` with `rain_next_4h_mm_actual` and `rain_next_4h_actual` fields) and matching indexes.
+- [x] [P0] Update prediction upsert SQL to write to the 4-hour prediction table/columns.
+- [x] [P0] Update monitoring views in `db/init/002_rain_monitoring_views.sql` so drift/calibration/pipeline-health views include the 4-hour prediction path.
+- [x] [P0] Update Go DB query layer (`internal/db/series.go`) to read 4-hour prediction rows/fields.
+- [x] [P1] Update dashboard API defaults (`cmd/ingestd/web.go`) from `rain_next_1h` to the selected 4-hour model name (or make model name configurable).
+- [x] [P1] Update web UI labels/semantics (`cmd/ingestd/web/index.html`, `cmd/ingestd/web/app.js`) from “Rain 1h %” to “Rain 4h %” and verify chart legends/tooltips match the new horizon.
+- [x] [P1] Update worker/runtime defaults (`docker-compose.yml`, `scripts/run_rain_ml_worker.py`, `scripts/run_p0_rain_workflow.sh`) to use `rain_next_4h` naming/versioning.
+- [x] [P0] Update health-check defaults (`scripts/check_rain_pipeline_health.py`) for 4-hour evaluation latency (e.g., pending-eval age threshold > 4h).
+- [x] [P1] Update docs and runbooks (`README.md`, `docs/rain_prediction.md`, `docs/rain_model_runbook.md`) so commands, table names, and target definitions match the 4-hour system.
+- [ ] [P0] Run full retraining/evaluation for the 4-hour target and compare against current 1-hour model metrics before production cutover.
+- [ ] [P0] Execute staged rollout: deploy schema + views, deploy model + inference, verify dashboard/health checks, then switch default model name.
+- [x] [P1] Keep rollback path documented: retain `rain_next_1h` artifacts/table access until 4-hour monitoring is stable. (documented in `docs/rain_model_runbook.md` staged rollout/rollback section)