In some videos, I saw people play in autumn and winter background in summoner's rift, but I can only play at normal version whenever I join any game. Is there any way to change the season of the map?
Riot does it seasonally for fun.
I believe only time you chose a background is in custom games, unless they've changed it.
© 2015 Riot Games, Inc. All rights reserved. Riot Games, League of Legends and PvP.net are trademarks, services marks, or registered trademarks of Riot Games, Inc.