Hi Krispe!
I've often visited San Fransisco in the fall, to visit a friend who lives in Big Sur. Boating out to Alcatraz in November was like getting shot with ice bullets. If you can even look at the SF Bay in winter, then you can handle the water parks at Disney in December!
THe waterparks do each close for a period each winter, but not at the same time. The water is heated year round, so even if the air is cold, the swimming is fine. The lowest I've ever seen (daytime) was aboiut 63. And I swam!
Maybe someone will put up the refurb schedule here for you. I think BB closes in the November time frame, and TL in Jan or Feb, but I could be way off. But I know they don't close them because of weather. It's standard maintenance, and that's the time of year to be shutting them down for such a purpose. Those dang Floridians won't go in January. They actually think 65 is cold!