Definitely depends on schools. Emory doesn't start until October, Vandy's first one was like a week ago, Wake is booked through September, I think Pitt doesn't have any open slots until November... completely school dependent.
I've been complete at Pitt since July 2nd, and if I got an invite today, it wouldn't be until November. So it really just depends on when the school starts and how late they get to you.