So the top post right now is a glitch for the Winter Blizzard World. Here is how you can do it too :D

Blizzard World

METHOD:

1. Create a custom game. Open the settings menu, go to “Lobby”, and set “Return to lobby” to “Never”.
2. Open the Workshop editor. Create a new “Ongoing - Global” rule.
3. Add a “Wait” action, set for 20 seconds, then add a “Declare Match Draw” action.
4. Start the game.
5. Press Escape, and select Show Lobby. Open the custom game settings, and load the preset JTM06 (ENTER THIS CODE)
6. Exit the custom game settings screen. If it worked, you will see the usual “custom game settings updated” message. Don’t worry if you see error messages saying “invalid options” and it won’t let you restart the match—this is why you set the match to end in a draw after 20 seconds.
7. Wait for the game to end (again, it won’t take long at all) and let it restart. When it does, it should load you into Winter Blizzard World! (Or perhaps another winter map, but I’ve only seen Blizzard World.)

Special thanks to Flarn2006 for finding this.

P.S. Blizzard do not fix this please

EDIT: SY146 is a code for a chill server with the same map