Snorkeling in December?

Experienced cruisers ... would you recommend a snorkeling excursion for a December 3rd port call in Nassau? We've been to the beach during that time of year, but not out on a boat tour for snorkeling, and I'm wondering if it would be uncomfortably chilly. I know the weather can vary, but I'd love some input. Yay or nay to snorkeling in December?

Nassau's temps from oct-march are so iffy, I would wait and book it day of or day before if it's a ship's excursion. No matter what the temps, they will go out, but why be uncomfortable all day long?