Seasons

— Gustave Brione, mid 19th century

Happy winter solstice—or summer solstice if you’re in the Southern Hemisphere! Here are a dozen ways to enrich your campaign world and bolster verisimilitude with seasonal phenomena:

1. Don’t limit yourself to the seasons of the Gregorian calendar. I recently learned about the traditional Japanese calendar, which features 72 kō: highly specific microseasons bearing names such as “sparrows start to nest,” “rotten grass becomes fireflies,” and “crickets chirp around the door.”
2. Snowfall may render roads impassable, and so might snowmelt floods in the spring or floods/mudslides during the rainy season.
3. Like animals, monsters might migrate altitudinally, latitudinally, or to their mating grounds. Consider how people might respond to these migrations. For example, the Nunamiut people of Alaska followed caribou migrations for thousands of years.
4. Consider whether magic is subject to seasonal change.
5. Incorporate local winds into your world and consider what superstitions or actual supernatural phenomena might be associated with each.
6. Monsters in your world may hibernate or undergo a similar process.
7. Certain plants or mushrooms may grow or bloom only during brief windows.
8. Include seasonal festivals in your world. Dolmenwood does this well.
9. Monsters may have seasonal associations. Perhaps people in your world eagerly anticipate spotting the first bioluminescent cloud jellyfish of the winter.
10. Seasonal phenomena such as waterfalls or icicles may block dungeon entrances during part of the year.
11. During their mating season, monsters may become more aggressive and territorial.
12. Incorporate extreme weather events—real and/or fictional—into your weather tables. Don’t you hate oneiric thunder?