My birthday is 8/27 and DD1 is 9/4 (and DH is 7/3) so we've gone at the last week of August before and likely will again, and again (we are going in mid-late August this year). The heat does kind of suck, but we have little kids so we are usually up by 6 or 6:30, then we take an afternoon break, and then go back out around dinner time. To us, the lower crowds are worth it, and there are usually a couple days with afternoon thunderstorms anyway, which cools things down.