We don't do the waterparks as we feel it is still "too cold." Then again, we are from S. Louisiana and 70 is cold! We only do the water parks May-Sept. One year, we were there in Feb. and kids swam at the PO pool. The pool was heated though. I've seen people swimming in 30-40 degree weather in December with steam coming out of the pool and the ligeguards in Wind Suits/pants/jackets. I guess it depends on where you are from.
Lisa