diff --git a/src/Constants.tsx b/src/Constants.tsx
index c2ad21b..1122eb6 100644
--- a/src/Constants.tsx
+++ b/src/Constants.tsx
@@ -66,6 +66,7 @@ export const LOCATIONS = {
   },
 } as { [id: string]: LocationType };
 export const OUTSKIRTS_WIND_MULTIPLIER = 2; // https://github.com/toddmedema/electrify/issues/96
+export const EQUATOR_RADIANCE = 1000; // at sea level, equator, clear day, noon https://en.wikipedia.org/wiki/Solar_irradiance
 
 export const TICK_MS = {
   PAUSED: 250,
diff --git a/src/data/Weather.tsx b/src/data/Weather.tsx
index 1382e98..896946d 100644
--- a/src/data/Weather.tsx
+++ b/src/data/Weather.tsx
@@ -1,4 +1,4 @@
-import { DAYS_PER_MONTH, DAYS_PER_YEAR } from "../Constants";
+import { DAYS_PER_MONTH, DAYS_PER_YEAR, EQUATOR_RADIANCE } from "../Constants";
 import { DateType, RawWeatherType } from "../Types";
 import { getRandomRange } from "../helpers/Math";
 import { getSunriseSunset } from "../helpers/DateTime";
@@ -79,31 +79,48 @@ export function getWeather(date: DateType): RawWeatherType {
   };
 }
 
-// 0-1, percent of sun's energy hitting a unit of land relative to max at equator (~1360 w/m2)
 // Is later multiplied by cloudiness
+// TODO should this just take in cloudiness? The game knows future weather...
 // TODO change to watts per sq meter or some fixed value, and verify that it's returning reasonably accurate values per location and season
 // (hoping that day length alone is a sufficient proxy / ideally don't need to make it any more complex)
 // https://earthobservatory.nasa.gov/features/EnergyBalance/page2.php
 // indicates a roughly linear correlation that each degree off from 0*N/S = 0.7% less sunlight
-export function getRawSunlightPercent(
+// TODO fix the pointiness, esp in shorter winter months - Maybe by factoring in day lenght to determine the shape of the curve?
+// Day length / minutes from dark used as proxy for season / max sun height
+// Rough approximation of solar output: https://www.wolframalpha.com/input/?i=plot+1%2F%281+%2B+e+%5E+%28-0.015+*+%28x+-+260%29%29%29+from+0+to+420
+// Potential more complex model for solar panels: https://pro.arcgis.com/en/pro-app/3.1/tool-reference/spatial-analyst/how-solar-radiation-is-calculated.htm
+/**
+ * Calculates the raw solar irradiance in watts per square meter (W/m2) for a given date and location, not accounting for weather
+ * It first calculates the base irradiance based on the latitude, with a reduction factor for higher latitudes.
+ * It then gets the sunrise and sunset times for the given date and location.
+ * If the current time is between sunrise and sunset, it calculates the minutes from darkness (either sunrise or sunset, whichever is closer).
+ * It then calculates the irradiance based on a mathematical model that approximates the solar output as a bell curve.
+ * This model takes into account the time of day and the length of the day to approximate the height of the sun and the season.
+ * If the current time is outside of sunrise and sunset, it returns 0, indicating no solar irradiance.
+ *
+ * @param {DateType} date - The date and time to calculate the irradiance for.
+ * @param {number} lat - The latitude of the location to calculate the irradiance for.
+ * @param {number} long - The longitude of the location to calculate the irradiance for.
+ * @param {number} cloudCoverPercent - The percentage of cloud cover, from 0 to 100.
+ * @returns {number} - The calculated raw solar irradiance in W/m2.
+ */
+export function getRawSolarIrradianceWM2(
   date: DateType,
   lat: number,
-  long: number
+  long: number,
+  cloudCoverPercent: number
 ) {
+  let irradiance = EQUATOR_RADIANCE * (1 - 0.007 * Math.abs(lat)); // w/m2
+  irradiance *= 1 - cloudCoverPercent / 100;
   const { sunrise, sunset } = getSunriseSunset(date, lat, long);
   if (date.minuteOfDay >= sunrise && date.minuteOfDay <= sunset) {
     const minutesFromDark = Math.min(
       date.minuteOfDay - sunrise,
       sunset - date.minuteOfDay
     );
-    // TODO fix the pointiness, esp in shorter winter months
-    // Maybe by factoring in day lenght to determine the shape of the curve?
-
-    // Day length / minutes from dark used as proxy for season / max sun height
-    // Rough approximation of solar output: https://www.wolframalpha.com/input/?i=plot+1%2F%281+%2B+e+%5E+%28-0.015+*+%28x+-+260%29%29%29+from+0+to+420
-    // Solar panels generally follow a Bell curve
-    // Potential more complex model for solar panels: https://pro.arcgis.com/en/pro-app/3.1/tool-reference/spatial-analyst/how-solar-radiation-is-calculated.htm
-    return 1 / (1 + Math.pow(Math.E, -0.015 * (minutesFromDark - 260)));
+    return (
+      irradiance / (1 + Math.pow(Math.E, -0.015 * (minutesFromDark - 260)))
+    );
   }
   return 0;
 }
diff --git a/src/helpers/Energy.tsx b/src/helpers/Energy.tsx
index a5bd7a2..3ecbc48 100644
--- a/src/helpers/Energy.tsx
+++ b/src/helpers/Energy.tsx
@@ -1,4 +1,4 @@
-import { OUTSKIRTS_WIND_MULTIPLIER } from "../Constants";
+import { EQUATOR_RADIANCE, OUTSKIRTS_WIND_MULTIPLIER } from "../Constants";
 
 export function getWindOutputFactor(windKph: number) {
   // Wind gradient, assuming 10m weather station, 100m wind turbine, neutral air above human habitation - https://en.wikipedia.org/wiki/Wind_gradient
@@ -15,12 +15,16 @@ export function getWindOutputFactor(windKph: number) {
   return windOutputFactor;
 }
 
-// Sunlight percent is a proxy for time of year and lat/long
+// Since solar panel nameplate wattages are usually rated at peak output at equator noon, we use that as baseline
 // Solar panels slightly less efficient in warm weather, declining about 1% efficiency per 1C starting at 10C
-// TODO what about rain and snow, esp panels covered in snow?
+// TODO what about rain and snow, esp panels covered in snow? We should update irradianceWM2 based on weather when it's originally calculated...
+// but that still means we'd need to track some additional historic value of "even though it's not currently snowing, they're still covered in snow"
 export function getSolarOutputFactor(
-  sunlightPercent: number,
+  irradianceWM2: number,
   temepratureC: number
 ) {
-  return sunlightPercent * Math.max(1, 1 - (temepratureC - 10) / 100);
+  return (
+    (irradianceWM2 * Math.max(1, 1 - (temepratureC - 10) / 100)) /
+    EQUATOR_RADIANCE
+  );
 }
diff --git a/src/reducers/Game.tsx b/src/reducers/Game.tsx
index fae99b4..e7a2cca 100644
--- a/src/reducers/Game.tsx
+++ b/src/reducers/Game.tsx
@@ -22,7 +22,7 @@ import {
 import { arrayMove } from "../helpers/Math";
 import { getWindOutputFactor, getSolarOutputFactor } from "../helpers/Energy";
 import { getFuelPricesPerMBTU } from "../data/FuelPrices";
-import { getRawSunlightPercent, getWeather } from "../data/Weather";
+import { getRawSolarIrradianceWM2, getWeather } from "../data/Weather";
 import { dialogOpen, dialogClose, snackbarOpen } from "./UI";
 import {
   DIFFICULTIES,
@@ -530,9 +530,12 @@ function reforecastWeatherAndPrices(state: GameType): TickPresentFutureType[] {
       return {
         ...t,
         ...fuelPrices,
-        sunlight:
-          getRawSunlightPercent(date, state.location.lat, state.location.long) *
-          (weather.CLOUD_PCT / 100),
+        sunlight: getRawSolarIrradianceWM2(
+          date,
+          state.location.lat,
+          state.location.long,
+          weather.CLOUD_PCT
+        ),
         windKph: OUTSKIRTS_WIND_MULTIPLIER * weather.WIND_KPH,
         temperatureC: weather.TEMP_C,
       };
@@ -583,8 +586,6 @@ function updateSupplyFacilitiesFinances(
     now.temperatureC
   );
 
-  console.log(now.minute, now.sunlight, solarOutputFactor);
-
   // Pre-check how much extra supply we'll need to charge batteries
   let indexOfLastUnchargedBattery = -1;
   let totalChargeNeeded = 0;