On the UO side most rides are indoors with the exception of the kids area which has the Woody Woodpecker coaster and then RPR
On the IOA side, it is about opposite. Most rides seem to be all or partially outdoors which the exception of Spiderman, Cat in the Hat and FJ.
Depending on when you go, it normally rains in Florida some part of the day but the good thing is that usually that rain goes away pretty quickly. If you have the park hopper and it is getting ready to get nasty head over to UO and do the indoor shows/rides. By the time you go on a couple the rain will more than likely be over.
We use the rain time as nap time for kids makes for a good excuse to walk back to the room for some R&R time.
NOTE: if you are staying onsite the boats will also shut down if there is lightning