Florida's sun can be unrelenting. If you are planning on renting a giant slide like the one pictured here, you will need to figure out how to deal with the sun. The tree in this photo had little effect on the slide, and it's obviously higher than the adjacent building. Therefore, when my kids went down this slide after noon, it had been heating up all day, and the slide itself actually left burn marks on the kids.
It might help to consider a photo like this when you're planning your giant slide location. I'd also look into the rules of setting it up. For example, if you can run a hose to make it a water slide (or just to cool it off once an hour), that might help. Or if you're allowed to use tarps along the south end of the slide, or even above the slide.
If the slide is a big deal to the event, you might want to even consider what time you even plan your event, but you'll certainly want to think about the direction of the sun when most kids are on the slide. I don't know if this works, but if it's really hot and sunny, maybe pillow cases for the riders' legs would be helpful. Or just tell anyone who's going to ride that they need pants, but that system probably only works if the slide is at a strict church (clothing-wise). I'm sure some kids stopped going down this slide, even though it was fun, since my kids had noticeable burns on their legs from going down two or three times each.
Maybe there's some way to erect a sail shade with wire cable and a big cloth. I don't know, but it's something to consider. And if your organization gets good at creating such a thing, maybe it would be a good volunteer opportunity to put some up in local parks.
