Hi. Tim....
I don't want to bust your bubble, but....... Feb is one of the nastiest months, if not the nastiest, for weather at Galveston. It can be really wet, windy and cold. At that time of year the surf water temp is around 50f. If you just have to get wet, you could try Offatt's Bayou. It is a protected area on the leeward side of the island, easily reached by car with easy entry. Vis will probably be 5-10 feet that time of year. The water temp may be a little warmer (less Movement and a little deeper than the surf area) If you like to eat stone crab claws there are some nice ones in Offatts.
Two other suggestions: Check out the Texas Swamp Divers Team site on this board. Maybe you can hook up with someone around the Houston/Galveston area that is making a dive while you plan to be in the area. Next, check with some of the LDS's and see if they have a flower gargen trip then. Also there is a lot of organized lake diving being done by different groups.
good luck.