We just went 1-3-04 - 1-10-04. We are from Arizona so also have thin blood! We thought the water was cold everywhere, but since we had already paid for the stingrays and the dolphin swim we went for it. Once you get used to it it is tolerable. My son did start to turn blue in Cozumel and had to get out. He tried to snorkel at CC and didn't last long - he is very thin (no blubber to keep him warm). Overall it was a great trip though - we would do it again!!!