Anahuac side has been a little too fresh from the Trinity Bay Run off this spring / summer.. it's starting to get a little better.. but it's pretty ugly over there. The only fish in east bay have been on the deep reefs closest to the boliver shoreline.. So Salinity is one factor.
Tides4 fishing has quite a few tide stations for Galveston. http://www.tides4fishing.com/us/texas
Probably your best bet for wade or walk in for right now will be the north or south jetties. Why.. becuase jetties are big fish holding structures and with the bay as fresh as it's been, the jetties have been on fire this summer. In addition, you're coming up to the bull red run.. it's about 2 months out but you might start catching some early stragglers. Best is Sept - Nov.
There's a lot more to consider. feel free to email me any of your questions,