Tundra

Tundra only appears in worlds that were generated during the holiday season, or in a 1 in 3 chance at any other time of the year. It is the only biome that grass does not grow in, and in place of dirt there is snow. Also, this is the only biome that has an animated graphic, which in this case is it snowing. There is currently no background art for the Tundra biome.