Rain does not actually produce new water tiles, does not cause existing water levels to rise, and has no effect on lava or honey tiles, but it does spawn some unique enemies or enemy variants, and certain critters behave differently. There are however some functional effects. Rain is primarily an aesthetic effect, only visible on the surface: It displays Rain/Blizzard graphics, darkened ambient sun/moon light, and altered music. When a player is in a Snow biome during Rain, it appears as a Blizzard, causing snowfall volume to increase. Each Rain event lasts for 24 in-game hours (24 real-world minutes), spanning both day and night portions. Rain occurs randomly and affects all surface biomes for its duration. I hope it doesn't rain again until this paint dries.
