diff --git a/CLAUDE.md b/CLAUDE.md
index 75320e14..9e38f257 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -110,19 +110,20 @@ mix assets.deploy        # minified + digest
 
 ### Scoring Algorithm
 
-9-factor weighted composite score (0-100) per grid point per band:
+10-factor weighted composite score (0-100) per grid point per band (recalibrated 2026-04-11 via gradient descent):
 
 | Factor | Weight | Source |
 |---|---|---|
-| Humidity | 20% | HRRR surface temp + dewpoint |
-| Time of day | 20% | UTC hour, cyclical |
-| T-Td depression | 12% | HRRR surface |
-| Refractivity | 10% | HRRR profile gradient (thresholds calibrated for HRRR resolution) |
-| Sky cover | 10% | HRRR cloud cover |
-| Season | 10% | Month, band-dependent (inverted for 24G+) |
-| Rain | 8% | HRRR precipitation, ITU-R P.838-3 |
-| Wind | 6% | HRRR 10m wind |
-| Pressure | 4% | HRRR surface pressure |
+| Rain | 13.6% | HRRR precipitation, ITU-R P.838-3 |
+| Humidity | 12.4% | HRRR surface temp + dewpoint |
+| PWAT | 11.3% | HRRR precipitable water (column-integrated) |
+| Season | 11.1% | Month, band-dependent (inverted for 24G+) |
+| Refractivity | 10.5% | Native HRRR dM/dh (10-50m), fallback to pressure-level (250m) |
+| Pressure | 10.3% | HRRR surface pressure (frontal activity proxy) |
+| T-Td depression | 9.8% | HRRR surface |
+| Sky cover | 8.0% | HRRR cloud cover |
+| Wind | 8.0% | HRRR 10m wind |
+| Time of day | 5.0% | Solar-time adjusted diurnal cycle |
 
 Humidity effect reverses by frequency: beneficial at 10 GHz (refractivity), harmful at 24+ GHz (absorption).