July is when we always go. There's not enough fingers and toes on everybody to count the number of times we've gone in July. Personally this is when I love to go to Disney. We've been when its not so crowded, and I sorta miss seeing a lot of people. I'm a "people watcher" person, and love talking to as many people as I can while there. I've meet people from all over the world, and in one case at DLP, we ran into one of my daughters school classmates there.
Like kimkarli, we're also from Texas and "hot and humidity" are not an issue for us. Yes there are a lot of people then, but its not all that awful. You learn to pace yourself, keep hydrated and take those afternoon breaks. If you do the parks like a commando, you'll suffer for it.