This was exactly what I was trying to research. I would not be concerned with 77. But my question would be is it dangerous at 62? We opened our pool here in MA this past Memorial Day weekend and it was about 85 outside and of course the kids wanted to go in. Last year was our first summer opening it and the kids went in then too (at 65) I make them get out every so often and run around and warm up, but their lips turn purple. Is this bad? I am sure the ocean around here never gets up to the 70's especially not til the end of summer? Please if someone knows anything, let me know so that I can tell them they need to wait. I got my solar reel today and the solar cover is coming tomorrow, I hope that will help quickly. Last year the temp stayed around 80 come july and august. We get full sun 7am - 7pm.