Dungeon Master: In-Game Weather

Typically, in the games I have played in, weather does not have a meaningful role besides adding to the atmosphere (despite D&D 5^th edition, the newest edition at the time I am writing this, having a fatigue system). Sometimes, weather is completely left out and not even mentioned over the course of the entire campaign. As I result I thought it fit to go over some general strategies to let weather play a bigger role. As usual, this piece applies to all tabletop role-playing games but will have an emphasis on D&D 5^th edition.

When to Use It

Unless the campaign is set somewhere that would make the weather a constant factor, making it have a mechanical effect should be used sparingly. There is going to be certain types of campaigns were it will need to play a major role at almost every turn (a campaign in the desert or on a ship). For the majority of them, however, the weather will mostly create atmosphere. In these kinds of cases one or two lines describing the weather and how it affects players would be enough (interlacing this with character actions also makes it feel more thematic). I would also say that weather should only be described when the weather changes, when it directly affects an action they are taking, or when players ask. Having the weather change, villagers comment on it and the occasional extreme helps flesh out regions and in campaigns were there is a lot of travelling, helps give each area an identity.

When to Use a Fatigue System

Naturally, if the weather somehow makes the characters hungrier, thirstier or more tired more quickly and the rule system already has a fatigue system (D&D 5^th edition, I'm looking at you), it is straight forward to apply that same system. If it doesn't you'll have to make one up, applying penalties you think are fair. It is also worth noting if the effects can be lessened or ignored by travelling slower and more carefully (either giving advantage to the check, ignoring the check all together, or rolling checks less often).

When Not to Use a Fatigue System

I generally say that if the effects of the weather go away when characters step indoors, then the fatigue system shouldn't be used. This gives the Dungeon Master more freedom to have effects for strange and possibly magical weather (for those times you find yourself on an alternate plane of existence). Most of the time, the major effects will be penalties to perception checks to see people in the distance and perception checks for detecting creatures for the purposes of determining surprise (in this case, I would suggest to use the concealment system currently in D&D). However, the weather could add additional penalties or bonuses. The weather and type of terrain will also determine how far away you would have to be for concealment to apply (open plains and a very clear day would allow for very long distances). An example of a bonus would be a particularly good day for sailing may increase the speed a ship moves.

Conclusion

Though this is shorter than my usual pieces, I hope it got people thinking about weather as an element of a campaign or session. In the case of areas with mild weather, I feel using such elements can really add to a game and help build the world. In campaigns built around extreme environments, I feel it can make a game memorable. If there are particularly good examples of weather being used in your games, I would love to hear them.