I live in a hot, humid part of the country, and I'm planning on how to deal with the heat and humidity in Florida.
We spend most of the summer, and even our summer vacations, in our home state of Texas. Normally, summer vacations involve lots of swimming, which keeps us cool. Florida, however, will be a theme park trip. We will not get the cooling towels and misting fans. I think those kinds of things make it worse. Our plan, based on the times we have done theme parks in the Texas summers, is to drink lots of water, ride a lot of indoor rides and see indoor shows in the middle of the day, and dress in light-weight clothing.
I also plan to pack a small cooler with water and ice. I know it won't last long, but it will help us to have something quick for grabbing an extra drink when we are in a hurry to get to one place or another and can't grab disney's free ice water.