Dungeons & Dragons Online

Is random weather in role-playing games too random? Using simple Markov chains to make RPG weather more realistic

Weather is important in role-playing games. This is especially true in wilderness and seafaring exploration adventures, where poor weather can affect navigation, travel speed, and visibility. Nearly all RPGs provide some way to randomly generate weather. One of the problems with random weather tables is that they tend to be “too random”. Rolling once a day on a random weather table can result in the weather jumping unrealistically between different types (Storm! Cold Weather! Hot Weather! Storm! etc). Real weather tends to vary over a few days, for example, mid-latitude weather tends to flip between regimes of unsettled stormy weather and regimes of settled weather (for example, heatwaves in summer or cold spells in winter associated with anticyclonic conditions).

“Less random” random weather using a simple Markov chain

A different way to create random weather and yet retain realistic variations is to expand on the idea of the weather flipping between “Settled” and “Unsettled” regimes using a method known as a Markov chain. The basic idea is that there is one roll per day to determine if the weather remains Settled or Unsettled, or if it flips to the other weather regime. There is then a second roll to determine the weather type. The second roll is done every day during an Unsettled weather regime to mimic the passage of storms and weather fronts. During a Settled regime, only one roll is made for the weather type, which then persists until the weather flips to the Unsettled regime again.

The tables below describe a method for generating realistic spring or fall (autumn) weather for a location similar to Southern England. Hopefully you’ll find this fairly simple to follow (or at least no more complicated than other RPG methods) – let me know in the comments.

Spring and Fall Weather Tables

  1. Roll 1d20 each day to determine if the weather remains Settled or Unsettled, or if it changes regime.
Roll 1d20Settled Weather RegimeUnsettled Weather Regime
1-14Weather remains SettledWeather remains Unsettled
15-20Weather becomes UnsettledWeather becomes Settled
  1. Now determine the type of weather, which depends on regime:

For a Settled Weather Regime:

At the start of the regime, roll 1d20 to determine the type of Settled Weather. The type of Settled Weather persists until the weather becomes Unsettled.

Roll 1d20TypeConditions
1-5Cool & FoggyNo rain, morning fog then clear, calm, cool
6-10Clear & CoolNo rain, clear, calm or light wind, cool
11-15Clear & WarmNo rain, clear, calm or light wind, warm
16-20Cloudy & WarmNo rain or light showers, cloudy, light wind, warm

For an Unsettled Weather Regime:

Roll 1d20 each day to determine the type of Unsettled Weather.

Roll 1d20TypeConditions
1-6Clear & dryNo rain, clear, light wind, cool
7-11Rain showersRain showers, cloudy, light wind, cool
12-17RainRain, cloudy, light to moderate winds, cool
18-20StormHeavy rain, cloudy, moderate to strong winds, cool

More details of the method can be found in the following blog post.

Some additional tables for summer and winter weather can be found here.


Similar Guides

    None Found

More about Dungeons & Dragons Online

Post: "Is random weather in role-playing games too random? Using simple Markov chains to make RPG weather more realistic" specifically for the game Dungeons & Dragons Online. Other useful information about this game:

Top 20 NEW Medieval Games of 2021

Swords, dragons, knights, castles - if you love any of this stuff, you might like these games throughout 2021.

10 NEW Shooter Games of 2021 With Over The Top Action

We've been keeping our eye on these crazy action oriented first and third person shooter games releasing this year. What's on your personal list? Let us know!

Top 10 NEW Survival Games of 2021

Survival video games are still going strong in 2021. Here's everything to look forward to on PC, PS5, Xbox Series X, Nintendo Switch, and beyond.

You Might Also Like

Leave a Reply

Your email address will not be published. Required fields are marked *