I was there the last week of July last year and it never got into the 90's and I need a bit of humidity (Indiana keeps my nose bleeding most of the year). Anyways, it was warm, but not unbearable. THe lines weren't horrible, just make good use of fast passes. We never waited standby for more than about 20 minutes and did all the mountains a couple times. Longest lines were in Fantasyland, Peter Pan and Pooh were about 45-50 mins so we got FPs before going back to hotels for an afternoon nap/swim around 1-2pm. We usually head back about 4-5 thereby missing the strongest sun of the day.
Jan '07 Pop Century, Mar '07 Day Trip, April '07 Off Property, May '07 OKW, July '07 POR, Oct '07 Pop Century (& MNSSHP!!!), Dec '07 Day Trip
Jan '08 POR
Feb '08 Pop
Mar '08 Off Property
April '08 AS Sports - I think - still gotta book it