Talk:Summoner/@comment-201.42.164.154-20120730214651/@comment-87.208.192.150-20120927200315

At any given time, it is not certain who the champions will be in the freeweek, but most of the time, a new champion will be free two weeks after it was released. Other than that most champions that are only 450 or 1350 IP are often in the rotation, as it is mostly meant to give enough options for new players. Usually there will also be at least one 6300 IP-champ in the rotation to let you try them out. Most commonly this is way before you purchase them, or you would have to use RP.

All in all there is no real pattern, but you could find consistencies if you look, and make an educated guess.