Hi! Living in FL I would say just keep in mind that it's HOT and HUMID and rains about every afternoon for a short while.
So dress comfortable, hats are good, sunscreen & sunglasses are necessary. Bring them if you can, or get them when you get to FL, because Disney charges a small fortune for them in the world.
Bring rain capes & throw some lightweight flip flops in a bag, and you won't have a problem getting around mid-afternoons, sloshing through the puddles. A small battery-powered water bottle with fan outfit is a great way to cool down.
Also remember August is pretty crowded so be patient, make a plan of attack for what you want to see so you're not running back & forth all day (wears you out and wastes time), and make ample use of EMH & FPs to cut down on wait time & crowding.