MOST schools start their interview cycle in October, and they will go all the way until March next year.
A FEW schools start in August (I can think of LECOM and ARCOM).
The individuals I know that received the August interviews had completed primaries by June 15th (this is when D.O. schools can view the AACOMAS) and had completed secondaries by the first week of July.
LECOM sent it's first interview invitations out in late July last year.
Long story short, the longer you wait, the more applications there are in line ahead of yours to be looked at by admissions committees. Apply as early as possible, so long as your application is ready.