I guess that would depend when you are diving. In late Feb. early March the water temp. was around 78 degree F. I wore a shorty and was quite comfortable. Doubtful this time of year but # of dives, depth and personal comfort are all things to consider. I will be back in late July and will have mine just in case. I don't think the water temp. varys a great deal although I do expect it's a little warmer now. Enjoy yourself.