1. TOO HOT! I live in Canada, I can get that nice weather down here during summer, and I hate missing summer down here. It's great to be able to escape the horrible cold, rainy & snowy weather in the winter/spring.
2. WAY TOO BUSY! A lot of people go down there on summer break, but we always go in April right after Spring Break, so there's hardly anyone down there.
3. Hurricanes. Sure, Disney is probably the safest place to be during a hurricane, but you wouldn't be able to do very much if there was one.