Some of my best coaster memories are of coaster rides while it was raining, with the one time special effect of water slamming into me. Actually increases the thrill. Here in the northeast, all of our parks are primarily coaster parks with 'very few if any' indoor attractions, and it rains nearly as much as it does in Florida, and we have lots of thunderstorms which occasionally creates a period of downtime. But, if you want a long coaster, the weather is part of the price. As I said before, I doubt anyone is going to put up a 7 to 8 acre building to accommodate a coaster. The added building cost would really take away from any theme budget.