We were also there on those dates last year. I know that heat is intolerable for some people, but I thought the temperatures were very comparable to what we were experiencing in New Jersey before we left! It's not uncommon to have 90 degree temperatures (and above) in NJ in the summer. (And we also get the humidity that everyone complains about.) We were really use to the heat before we left, but still took frequent breaks and didn't try to accomplish too much at once. We did have storms almost every day, but it gave us an excuse to explore the inside of our resort and provided built in down time. The water parks were somewhat crowded, but still manageable. The theme parks were more crowded than I expected, but as everyone says, use Fastpass and realize that Disney (hopefully) isn't going anywhere! You'll have a great time!