Texas

Texas runs the western Gulf of Mexico from the Sabine River at the Louisiana border around the long curve of the coastal bend at Galveston, Matagorda, and Corpus Christi, down to the Mexican line at South Padre Island. The tide signature here is one of the smallest and strangest in the lower 48 — a primarily diurnal pattern with a mean range close to 0.4 metres at Galveston Bay Entrance and similar at the other gauges down the coast. Most days produce one clear high and one clear low, with a smaller secondary excursion that often barely registers. The barrier-island geometry — Galveston Island, Matagorda Peninsula, Padre Island — separates a chain of shallow bays and bayous from the open Gulf, and tidal exchange happens through narrow passes that concentrate flow into sharp currents on the change of tide. Fishers working the Galveston jetties or San Luis Pass time their out-and-back to the change. Hurricane season runs June through November and tropical-storm surge can stack two metres or more on top of the tiny astronomical signal, which is why the National Hurricane Center is the authoritative source during landfall events. NOAA CO-OPS runs the Galveston Bay Entrance gauge; the harmonic predictions on this site assume normal weather.