We always snorkel whenever we go. Trick is to keep moving and come out into the sun.
I get chilly so I wear a "skin" sold in scuba shops and over that a "shortie" wet suit, sold in many sporting goods stores, primarily for water skiers I think.
If you are actively swimming and down in the water, you will be fine. Cloudy, windy days are no fun, cause you can not get warmed up.
Even a long sleeved shirt that fits tightly can help hold some warmth. Plan ahead, crack a coconut and dig out some meat before you start, then eat a bunch when you are drying out.
Works every time for me. In my experience the "warmest" place to snorkel is beach behind Harbour Lodge in Hopetown, cause shelteered from the wind and also gets a lot of sun.

Follow Ups:

Re: Swimming and swimming PeteR 20:04:07 11/11/98 (0)