add barometric pressure

internal/providers/wunderground.go

@@ -33,6 +33,7 @@ type WUUpload struct {
 
 	RainLastHourMM float64
 	DailyRainMM    float64
+	PressureHPA    *float64
 
 	DateUTC string // "now" recommended
 }
@@ -63,6 +64,11 @@ func (c *WundergroundClient) Upload(ctx context.Context, u WUUpload) (string, er
 	// UV index
 	q.Set("UV", fmt.Sprintf("%.2f", u.UVI))
 
+	// Barometric pressure (inHg)
+	if u.PressureHPA != nil {
+		q.Set("baromin", fmt.Sprintf("%.4f", hPaToInHg(*u.PressureHPA)))
+	}
+
 	// NOTE: your WS90 payload provides light in lux, not W/m^2.
 	// WU expects solarradiation in W/m^2, so we omit it unless you add a conversion/actual sensor field.
 	if u.SolarWm2 != nil {
@@ -110,3 +116,6 @@ func (c *WundergroundClient) Upload(ctx context.Context, u WUUpload) (string, er
 func cToF(c float64) float64     { return (c * 9.0 / 5.0) + 32.0 }
 func msToMph(ms float64) float64 { return ms * 2.2369362920544 }
 func mmToIn(mm float64) float64  { return mm / 25.4 }
+func hPaToInHg(hpa float64) float64 {
+	return hpa * 0.0295299830714
+}