Our experience is that when you are in the water its fine, but out of the water is cooool. I see you have little ones, maybe swim and then make a mad dash for the heated room!! We've even stayed in the pools longer 'cause we dreaded the air hitting us. It makes for fun shrieks and giggles though!!
As for the water parks, we did it once and won't again. You just don't get the full enjoyment of the water park with the cooler weather and wind.