Hot and crowded, but we usually go in July due to scheduling. The best advice was one post that said start out really early in the morning, go back to the room about noon, and venture back about 4:30. This will keep you inside or in the pool during the hottest part of the day. Also keep in mind that there is usually a thunderstorm everyday around 3 or so. It cools it off ever so slightly, but evenings can we very warm so pack accordingly.
You'll have a great time, just bring a lot of water and sunscreen.