Water temperature is definitely a personal preference, but typically pools used for competitive swimming are kept cooler at around 80F or so. Typical residential pools used for moderate swimming are usually kept around 84-85F or so. Pools used for therapy are usually kept around 88-90F or so. Our own pool is used mostly for "in-place" exercise and a small amount of swimming so is kept mostly at 87-88F. I find that 88F is the temperature where there is no "chill" getting into the water nor any "chill" from staying in the water over a long period of time. Obviously, doing any significant exercise at that temperature will make one feel too hot and it won't be "refreshing".

I'm amazed when kids can go into 70's water without a problem. I certainly was never that way, but then I was always very skinny.

Richard