We stayed at RPR Christmas week, 2008. The pool was heated, BUT the water sprayers in the kids' play area were not. Those sprayers were CHILLY, but the kids didn't care.
pool water is heated at HRH too but sometimes in the evenings the air is a lil cool in December...we seem to always get use out of the pool in the afternoons.
The pool is heated but the outside air is not. Brrrrrrrrr. (it was in the 30s and 40s during our stay last December...we were insane for swimming but we just coudn't help ourselves, and there were plenty of other insane people around us!)