The first week of February at the Dolphin (The Swan's sister resort) was one of our favorite trips to WDW yet! You should be fine to swim. If you get chilled, just hop out and get into one of their hot tubs (I think there are 3 in all!)
Just keep your eyes open for closings due to private parties/conventions. They'll usually give you a heads up at least 2-3 days in advance. Most of the time it's just the big Grotto Pool that is closed. The lap pools usually stay open for your swimming enjoyment. It just depends on the size of the party/convention.