Previews:

Mile 22: 1m
Alpha: 525k

Other:

Crazy Rich: 3.8m
Meg: 3.2m

The Hitman's Bodyguard made 1.65M on the same weekend last year (weekend prior to many schools starting) on its way to a 21m 3-day.

American made did close to 1m in late Sept. for 16.8m.

Mile 22 should do around 12-13.

Edit: Also Deepwater Horizon did 860k in late Sept. for 20m, so maybe Mile 22 can even hit 15 in late August.