WinterFest is a yearly event which is held during late December, lasting for two weeks. During WinterFest, the world GROWCH is inhabited by an NPC named Growch. When enough Winter Gifts are given to him, a few WinterFest items will be unlocked, thus making Growch happy and restricting gifts to be given to him for several hours.
Players can visit the Growch in worlds GROWCH1, GROWCH2, etc, similar to GROWGANOTH. Winter Gifts also spawn in worlds, depending on the amount of people in the world. During this time, the world select music changes.
In order to unlock some items and their recipes, players need to get the Growch's heart to a certain size before those items can be made. All splicable items or items which require a heart size to unlock can only be made during WinterFest.
During WinterFest, normal Ghosts are replaced with the Ghost of Winterfest Past. Upon contact, the player will have the "Frozen" mod active for 2 seconds, which is the same effect caused by a Snowball.
Tree Drops
Due to the introduction of the Giving Tree and Tree Decorations during WinterFest 2015, players could place Tree Decorations onto a Giving Tree, and, upon harvest, they could obtain special items. 1 Tree Decoration represents 1%.
| Item | Tree % |
|---|---|
 Winter Gift
|
0% |
 Snowcone
|
1% - 4% |
 Holly
|
5% - 9% |
 Snowflake Block
|
10% - 19% |
 Candy Cane Bait
|
20% - 24% or 60% - 69% |
 Twinkling Lights
|
25% - 29% |
 Hot Chocolate
|
30% - 39% |
 Winter Wind
|
40% - 49% |
 Elf Stockings
|
50% - 59% |
 Winter Robe
|
70% - 79% |
 Toboggan
|
80% - 89% |
 Weather Machine - Snowy Night
|
90% - 99% |
 Moose Cap
|
100% |
WinterFest Fish
Due to the introduction of the Candy Cane Bait during WinterFest 2015, new fish were introduced which can only be caught using the Candy Cane Bait. They include:
| Fish |
|---|
 Neon Squid
|
 Antarctic Icefish
|
 Gingerbread Fish
|
 Swedish Fish
|
 Mr. Narwhal
|
 Glass Piglet Squid
|