Public launch September 17 ahead of iPhone 6 debut.
Schiller on Apple's Yearly Product Timelines
Schiller, however, also admitted that having to come up with a "dazzling" show each January was unsustainable. He also admits that January does not fit into the Apple's natural product timelines, which he specifically spelled out:
He noted that Apple marches to certain annual product cycles: the holiday season (Novemberish), the educational buying season (late summer), the iPod product cycle (October), the iLife development cycle (usually March), the iPhone cycle (June).