CRSNDSNY said:
I went last July (we've only ever gone in January, May, September and December otherwise). Never again. It wasn't the heat so much for me as it was the
heat + the crowds.
If that were my only real exposure to Disney, I would probably never want to go back.
BUT, that being said...if that were the ONLY times we could go, perhaps we'd choose August because like Shan said, many southern schools are back in session at that time.
Any time from July until about mid-October can be beastly hot in Orlando. Think Atlanta or Washington, DC in the same time period and you won't miss it much. Florida is wetter, but the temps will be about the same. July, August, and September are in the "gruesome" range, with September probably being the worst.
I live in Miami, which a lot of people think is hot, but I have to tell you WE joke about Orlando weather.
Having said that, there are things you can do.
First, recognize the pattern -- it's hot in the morning (even for us), it's stifling around 1 PM, and then goes quickly through brutal to excruciating by about 4 PM. Then, the heat boils the clouds and the thunderstorms start. We don't have sweet little summer rains in Florida, we have thunderstorms. Lightning all around, huge claps of thunder, strong winds, and bucket loads of rain -- for an hour or less. Then -- and I hate to say "magically," but -- magically the thunderstorms subside and you have a nice, warm evening.
Obviously therefore, the prime times to be in the theme parks are first thing in the morning, and in the evening. Do character breakfast, attraction conquest, lunch and back to the resort, pool until the thunderstorms, and then theme parks at night, and you'll have a great time.
Second, drink a LOT of water. Start on the way to the theme park in the morning and don't ever stop. Your body is an amazing thing if you give it the water to work with. You'll have a lot more energy, and a lot fewer medical emergencies if you drink early and constantly. No place -- even WDW -- is fun when you're exhausted, and early and often water will alleviate a lot of that problem.
Third -- be prepared for the rain, and be realistic. First of all, you have to give up on waist-down. It's gonna be wet, get over it. It's only water and you are not the Wicked Witch of the West, so you won't melt. And you won't catch your death of cold -- germs make people sick, not water.
The best rain gear is a cheap PVC jacket with a hood. Second best is a $5 poncho. But forget waist-down. Umbrellas are good transportation devices (a la Mary Poppins), but useless for staying dry in a Florida thunderstorm. They either explode or carry you away, and the rain is coming in horizontally anyway, so the only dry part of an umbrella is likely to be the top.
If you MUST (for whatever reason) be in the theme parks in the afternoon, try to use at least a pinch of common sense. Plan on spending mid-afternoon enjoying those attractions which keep you indoors (dry and in air conditioning) for long periods -- the theater type attractions, as opposed to the outdoor ones.
I've been a little lighthearted about rain, but don't play with lightning. If there is lightning
anywhere in the vicinity, get indoors and stay there until it passes. Don't try to be cute, counting the interval between flash and thunder and multiplying by 1000 yards -- lightning often strikes several miles apart in the same storm. Lightning will fuse the car keys in your pocket together, and you are going to have a heckuva time getting the car started. Stay indoors.
If you start with a realistic attitude, take care of your body, and use a little common sense, you can have a great time at WDW in mid-summer. To be stupid is to be miserable...or worse.
, but the crowds are less then earlier in the month. I am hoping, of course, for no hurricanes this year. Maybe we will see them there. 
Good Luck!
but oh well, that's the beauty of 
Oh, but not the lightening!!! 
