The forecast for Central Florida, beyond about 36 hours, is useless.
Summer, as mentioned, is pretty monotonous---hot, humid, with afternoon pop-up thunderstorms.
There is a potential depression forming, but on its current track at worst it will bring some rain. If it rains, put on your poncho. We check into VWL on Friday. We know the rain could be coming. We don't care.
You'll still have a good time! We went to a Pirate & Princess one year in a *torrential* downpour (and being February it was a little cold, too). Had we not pre-paid for the tickets, we wouldn't have gone. But, it was incredibly fun. The rain let up just in time for the (slightly delayed) parade/fireworks, and the park was so empty you could have stood in the middle of Main Street during the fireworks, swinging a dead cat, and not hit anyone.