Rain

Rain is a type of weather that occurs somewhat randomly during summer. It has various effects on the game world and Wilson's Sanity. The chance of Rain can be predicted by building a Rainometer, much like the Winterometer measures temperature.

Negative Effects
Wilson's Sanity  will slowly decrease by 1.3 every minute when it is raining. This can be counteracted by equipping an Umbrella. Rain also reduces the effectiveness of Campfires and Fire Pits, causing them to burn out more quickly. If the rain is especially strong lightning strikes may begin. Lightning will not strike Wilson directly however it will strike any nearby object that can catch fire, such as Trees, Saplings, or burnable structures. If structures or plants are too close together, such as in a Berry farm, lightning can quickly cause a devastating fire.

In Rain fuel burns faster (depending on precipitation rate)
 * Fire Pit up to 200% faster
 * Campfire up to 250% faster
 * Torch up to 150% faster

Positive Effects
In Rain Farm crops grow up to 300% faster (depending on precipitation rate). Additionally, Mushrooms that have already been picked will only regrow after it rains.

Rain That Ribbits
Rarely, currently only in the Surprise! Story Preview Test, Frogs  will rain from the sky, appearing everywhere, this is very dangerous because frogs attack the player when they are too close. It is advised to not wander too much during this type of rain.

Trivia

 * Rain was added in the A Little Rain Must Fall update, funnily, as Snow, another form of precipitation, came in the previous Winter update.