Weather
For a given location and season, assign three ratings:
- Average Humidity as a percentage of relative humidity (
1–100). - Average Temperature as roughly degrees Fahrenheit (
1–100). - Instability as an estimate of how dynamic the weather is (
1–10).
You’ll also track a moving value: Pressure, which starts at 0.
Each day, roll d100 twice:
- Precipitation: roll between Pressure and Average Humidity:
- ≤ Average Humidity: mostly cloudy with rain.
- > Average Humidity: clear or partly cloudy, no rain.
- Critical: heavy clouds, substantial rain.
- Fumble: no clouds, bone dry.
- ≤ Pressure: storm clouds gather.
- Temperature: roll between Pressure and Average Temperature:
- ≤ Average Temperature: a warm day.
- > Average Temperature: a cool day.
- Critical: a warm front.
- Fumble: a cool front.
- ≤ Pressure: strong winds pick up.
- If both rolls ≤ current Pressure: a storm breaks. Reset Pressure to
0. - Pressure grows:
- If no storm broke, increase Pressure by Instability.
- If either roll ended in
0, double that increase.
If you want exact temperatures in degrees Fahrenheit:
- Derive once per location/season:
- Base Spread:
(100 - Average Humidity) / 2 - Swing:
Base Spread / 2
- Base Spread:
- Then each day:
- High:
Average Temp + Swing * (Avg Temp - Temp Roll) / 100 - Spread:
Base Spread - Swing * (Avg Humidity - Precip Roll) / 100 - Low:
High - Spread
- High: