Florida starts to get hot about May or so. And Florida heat is hot - oppressively hot in the summer time, especially if you're not used to it.
Most years it rains for 10-15 minutes in the afternoon, just enough to get the humidity back to 99%, then the sun comes out to roast you alive.
So now to May is better than the height of summer if you don't like the heat. Everyplace has AC so it depends what you're doing.
For the parks, sometimes the heat can clear things out. It wears out the Yankees such that after a 125 dollar dinner of fries and burgers, Dad is hot, tired, and PO at having spent a fortune that day, so it's back to the room, leaving the park much less crowded at night.
Orlando is far inland enough that it won't get a direct hurricane hit like a place on the coast. Height of hurricane season is August and September. Not much chance of one really impacting your visit, and worst case, you just leave early, so I would not bother factoring that in.