We had been going during the 2nd-3rd week of August for about 4 years in a row & finally decided to never go in August again because it just became insufferable. The 'free dining' offer usually runs August/September-ish and it was just CROWDED, CROWDED, CROWDED. Normally I can handle some crowds but add on top of that LITERALLY 92-98 degree weather, PLUS 80% humidity & tropical systems with heavy rain nearly everyday and we were just DONE! Not to mention more than several years ago one of our trips got really messed up because of a hurricane passing through so now I get nervous about hurricane season every year.
That being said, I would never go in July either because that seems like the peak of summer madness.
If you can squeeze in there during early June before everyone gets out of school in the northeast I would assume that's your best bet. We go to Disneyland in June during that time and have really good luck, the big summer crowds never seemed to pour in yet.
I've never been to WDW during those days leading up to Labor Day because I am a teacher & we always have either professional training sessions or meetings so I can't advise on those days.
Good luck.
