I am a 50-something grown up kid who doesn't like to be cold, and I've been in the pool at WDW the past two Decembers. In 2002, it was just too cold. It was cold enough that I had on a hat and gloves at MGM while viewing the Osborne Lights, and I was still freezing. In 2003, it was actually hot most days (the first two weeks of December), and last year it was very warm at the beginning of our trip, but the day we left it was really cold. This year we're heading down in November, and I plan to hit the pool at least two of the three days we'll be there.