Weather in RPGs – Advice, Generators, and Tables

Bad snow storms and extreme weather scuttled many a Game Day over the years. They throw our RPG gaming lives into chaos, and while being able to fall back to Roll20 can help the game go on … it’s useless when it comes to shoveling snow or bailing out the basement.

Just as a Nor’easter can play havoc with our ability to throw dice, so can weather affect our in-game characters.

In fact, I make sure it does by including weather in my RPG campaigns.

D&D, Weather, and Greyhawk

For me and Dungeons & Dragons, my random weather generation experiments began with the World of Greyhawk and the Glossography supplement from the 1983 boxed set. It includes a number of tables for generating weather, modified by terrain (e.g. coastal, mountains) and latitude. I used the weather tables sporadically in the early days of my campaign because it was an intensely manual (if fun) process. Today, I use the Weather Forecaster for Greyhawk World. It randomly generates a month’s worth of weather, using the Greyhawk calendar and all of the appropriate modifiers. it also incorporates the phases of Greyhawk’s two moons: Luna, which is white and large like our own, with a monthly cycle, and Celene, which is smaller, blue, and has a quarterly cycle.

I dump the results into a Google Sheet and then add columns for in-campaign events. For my Saltmarsh campaign, I added notes for:

  • Social drama on the streets of Saltmarsh
  • When particular campaign chapters began and ended
  • Random events taken from the Saltmarsh sourcebook

While some days the weather is just the weather, other days it leads to notable story developments. During that campaign,  two days of massive thunderstorms caught the town’s fishing fleet at sea. The town residents found themselves trapped indoors because of the heavy rains, and the various factions in town were forced to come into contact with one another … with the player characters in between.

The weather has inspired other stories over the years, including a multi-day blizzard that unexpectedly hit the fledgling frontier town of Obsidian Bay. The storm caught the players out in the countryside, forcing them to take refuge in an ogre-infested cave for several days, eating one of their horses to stay alive. Once they returned to the city, they found the town devasted by the storm. Much of its simple wood-and-thatch structures were destroyed, and the people were suffering from cold-induced maladies. The humanitarian crisis inspired the heroes to undertake a diplomatic mission to a nearby country to solicit aid. It ended up being one of the more memorable arcs in that campaign and it was all because of a few throws of the virtual dice.

The weather doesn’t need to drive the story; it can also influence it. Like many games, Dungeons & Dragons includes skill and combat modifiers based on weather and other environmental effects. A ho-hum fight against goblins can become a lot more challenging when whipping rain blinds the combatants, sudden gales force arrows off course, and the mud-slicked ground turns a gentle slope into a treacherous footing. It’s well worth checking out the weather rules for your own games to see how they might be used in your encounters.

RPG Weather Generators

Automated Generators

  • Weather Forecaster for Greyhawk World: My go-to weather generator for my Greyhawk campaigns. It recreates the weather generation system from the Glossography in the 1983 Greyhawk boxed set.
  • Donjon: Weather Generator: Randomly generates weather based on seasons, with options for climate and frequency of supernatural events.
  • Reddit: RPG Weather Generator: daily weather based in reality, a year at a time.: A Google spreadsheet-based weather generator inspired by the weather system outlined in Dragon Magazine #137
  • Dwarven Automata: Random Weather Generator: A generator that lets you specify climate, season, month within that season, measurement system (Celsius and Fahrenheit), and the option to display the results on screen or as a text-file download.
  • Fantasy Weather Generator: This Pathfinder-based generator lets you choose the measurement system (metric or British imperial aka Celsius and Fahrenheit ), climate, season, elevation, and biome. It also includes options for forcing precipitation, adjusting the temperature within ran
  • PBE Games: Weather Generator: Creates a month’s worth of weather with options for temperature, precipitation, and winds.
  • Weather Generator (Google Sheet): A spreadsheet-based approach to weather generation. To use it, you make a copy of the Google Sheet, then update the default values for the current season,  region, skies, and temperature. The spreadsheet creates a week’s worth of weather.

Pen-and-paper-based Generators

RPG Weather Resources


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Lightning Storm from the Clouds in Dee Why, New South Wales, Australia. Credit:

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