3.0.2

Fix the Why It Feels calcs

assets/js/compute.js

@@ -330,15 +330,27 @@ export function computeWhyFeelsLike(row, env) {
   const { Ta, Tmrt, va, eh, precip, snow } = row;
   const r1 = (v) => Math.round(v * 10) / 10;
 
-  // Radiation - mean radiant temp above or below air temp.
-  const sunAndSky = r1(Tmrt - Ta);
+  // Environment-adjusted air temp (same as used in buildHourlyRows).
+  const TaEnv = Ta + (env ? env.taOffset : 0);
 
-  // Wind - UTCI with actual wind vs calm, holding Tmrt = Ta and RH neutral.
-  const ehNeutral = vaporPressureHpa(Ta, 50);
-  const wind      = r1(utciApprox(Ta, Ta, va, ehNeutral) - utciApprox(Ta, Ta, 0, ehNeutral));
+  // Sequential UTCI isolation — all deltas are in the same UTCI-polynomial
+  // space so they add up: Ta + environment + sunAndSky + wind + humidity
+  // + precipitation ≈ SunSoak (utciAdj), within rounding.
+  //
+  // Tmrt already has env radiation scaling (dirFactor/difFactor/globFactor)
+  // baked in from buildHourlyRows, so each delta automatically reflects
+  // the active Solar Model without any extra work here.
+  const ehNeutral = vaporPressureHpa(TaEnv, 50);
+  const base      = utciApprox(TaEnv, TaEnv, 0, ehNeutral); // ≈ TaEnv
 
-  // Humidity - actual vapour pressure vs neutral RH 50%, no wind or sun.
-  const humidity  = r1(utciApprox(Ta, Ta, 0, eh) - utciApprox(Ta, Ta, 0, ehNeutral));
+  // Radiation: effect of actual Tmrt vs no-radiation baseline (wind=0, RH=50%).
+  const sunAndSky = r1(utciApprox(TaEnv, Tmrt, 0, ehNeutral) - base);
+
+  // Wind: cooling effect of actual wind with solar present (RH still neutral).
+  const wind      = r1(utciApprox(TaEnv, Tmrt, va, ehNeutral) - utciApprox(TaEnv, Tmrt, 0, ehNeutral));
+
+  // Humidity: actual vapour pressure vs neutral RH 50%, with solar and wind.
+  const humidity  = r1(utciApprox(TaEnv, Tmrt, va, eh) - utciApprox(TaEnv, Tmrt, va, ehNeutral));
 
   // Environment modifier - explicit temperature offset from the env config.
   const environment = env ? r1(env.taOffset) : 0;
@@ -346,7 +358,7 @@ export function computeWhyFeelsLike(row, env) {
   // Precipitation soak penalty - negative or zero.
   const precipitation = precipPenalty(precip, snow, va);
 
-  return { sunAndSky, wind, humidity, environment, precipitation };
+  return { base: r1(base), sunAndSky, wind, humidity, environment, precipitation };
 }
 
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