We were at the world at the end of October on our first trip. The first couple of days it was cool, high about 65 (18 c). We still were in the pool at the Poly, even at night when the temps dropped a little. The breeze coming off the 7 Seas lagoon were nippy, but how do you keep kids out of the water?
Most of the trip it was very comfortable and the weather cooperated with our plans for taking advantage of the pool.