WEATHER GENERATOR 0.15 Day # Time of Day Cloudcover Wind MPH Degrees F Wind Chill Event Event Start Hours Duration
Select Climate                  
Select Season                  
Select Elevation                  
Close to a Pole?                  
Desert Biome?                  
Stable Temp Biome?                  
Force Precipitation?                  
Adjust Temperature?                  
Weaker Winds?                  
# of Days to Generate                  
Scripting by Christopher Page                  
Generation rules from Ultimate Wilderness © 2017, Paizo Inc.. License: OGL v1.0a . Send suggestions and bug reports to: cap708g at hotmail.                  
All temperatures listed in Fahrenheit.                  
Latitude of < 30 degrees = "Tropics", 30 to 60 degrees = "Temperate", 60 to 90 degrees = "Cold". As reference, N. Florida or N. Egypt is about 30 degrees and S. Alaska or S. Norway is about 60 degrees.                  
Elevation < 1,000 feet = "Sealevel", 1,000 to 5,000 = "Lowland"s, 5,000 to 10,000 = "Highlands", >10,000 = "High Mountains".                  
Weather "Days" start with Sunrise and end with Sunset. Weather "Nights" start with Sunset and end with Sunrise on the following morning.                  
Precipitation events with a sufficiently long Duration should be assumed to span into the start of the following Day or Night and  may cause events listed as Rain to turn into Snow events, or Snow events to turn into Rain events, which must be manually tracked.                  
Baseline daytime temperatures are typically supposed to last for multiple days. Generating a low numbers of days will disrupt this intented result.                  
2+ inches of snow adds 5 feet of movement cost per square, 12+ inches adds 10 of movement cost per square, 36+ inches cannot be walked through without snowshoes. Total accumulation must be tracked manually. Rainfall is not measured.                  
Thunderstorms and Thundersnow have a low, GM-detemerined chance of a Lightning Strike on players: 1/10 minutes for Thunderstorm and 1/hour for Thundersnow. Lightning strikes deal 10d8 Electricity damage, Reflex Save DC 18 for half, -4 on save if in metal armor.                  
For inclement Wind, Skill penalties apply per GM discretion, whick might stack with Peception penalties. Wind of 20 to 30 MPH impede Tiny creatures, 30 to 50 impede Small and may blow away Tiny, 50+ impede Medium and may blow away Small.                  
Thunderstorm Wind Speed is listed even when Tornados and Hurricanes are present. These rare secondary events occur during or after the Thundersorm and must be generated manually.                  
Due to days with constant sunlight or darkness, the system currently produces some erroneous results if area is near a Pole in Summer or Winter.                  
Alterations to Posted Rules                  
Baseline Winter temperature for Tropics was increased to 65 degrees to mostly remove the chance of frozen precipitation at night.                  
"Stable Temp Biome?" option was added to decrease temperature variations by about 40% for moderate Biomes such as Mediterranean.                  
"Drizzle" renamed to "Light Rain" and "Rain" renamed to "Medium Rain" to create a consistent naming convention.                  
"Windstorm" Wind Speed set to 51 to 74 as opposed to "51+" as "Hurricane" threshhold is 75.                  
"Duststorm" replaces "Sandstorm". Duststorm and Haboop and may occur in Deserts when there are high winds and no precipitation. Duststorm otherwise follows Rain rules.                  
Couldcover descriptions changed to "None", "Light", "Medium", and "Heavy" to create a consistent naming convention.                  
Maximum temperature for "Thunderstorm with Hail" liminted to 79.                  
Average Night temperature drops roughly doubled depending on Climate and Biome.                  
Previously absent Blizzzard effects added by extrapolation from other snow events.                  
For temperatures and wind with ongoing durations, a twice-daily variation of -3 to 3 was added.                  
Precipitation frequency for most categories increased by 5% each due to common elimination of fog events due to wind.                  
Decrease of Precipitation Intensity by 2 levels for "Dought" areas ignored, as Precipitation Frequency and Intensity were already very low.                  
Added "Force Precipitation?" option to manually adjust Precipitation frequncy. Precipitation events are still limited to one per 24-hour block, but often persist into the following 12-hour period.                  
Added "Adjust Temperature?" option to manually increase or decrease temperatures.                  
Added "Weaker Winds?" option to decrease frequency of inclement Wind by about 40%.                  
Added Wind Chill to output. I invite GMs to use this as the effective temperature when determining cold weather effects on characters outside of shelter.                  
Eliminated Tornados for Highlands and High Mountains.                  
Desert temperatures increased moderately for Day and decreased moderately for Night.