Autumn is one of the four seasons from the Reign of Giants DLC. It has a 50% chance to be the starting season instead of Spring. Autumn is mostly a peaceful season, comparable to Summer in the vanilla version of the game.
Autumn lasts 20 days by default, so the first Autumn lasts either from day 1 to 20, or from day 37 to 56. This will change if the length of the seasons is edited in the Preferences. Stages in Adventure Mode may have different seasonal variations.
During the majority of autumn, nights are short. This allows moving around more often without fearing the dark. It also means that less supplies are needed to survive the darkness.
During Autumn, the player does not have to worry about Overheating or Freezing, there is only occasionally Rain, Farm Crops grow normally, Walrus Camps are not active, Red Hounds may occasionally appear rather than Normal Hounds during timed Hound attacks, Redbirds and Crows appear, and the Koalefant appears with a red hide. Also, Birchnut Trees will start to lose their leaves, which change color, and fully-grown ones will yield extra Birchnuts when cut down. However, in Don't Starve Together, they have the highest chance of spawning Poison Birchnut Trees. Any resource such as Grass, Saplings, or Berry Bushes that withered in the Summer will return to their harvested state at the beginning of Autumn. Mini Glaciers begin to form during autumn.
Autumn leads to Winter, so players might want to spend their first Autumn preparing for the harsh weather that will soon be upon them.