March is a transitional month between winter and spring here on the coast. You could get cold, blustery wintery winds or the day could be calm, warm and sunny. Or you could have both.
Bugs won't be a problem (too early). Pesky seagulls could be a problem if you try to feed them. If you make the mistake and try to feed them, they'll never leave you alone. And they'll drop their calling card on you too.
You should have plenty of company from the spring break crowd. But the beaches are well patrolled and the rowdies tend to go across to Bolivar Peninsula.
Enjoy your visit to the Texas Gulf Coast. :cool: