Five flag colors tell you how rough the Gulf is on the day. Rip currents form next to jetties and piers, both ends of the island are closed to swimmers, and brown water is mostly silt, which tells you nothing about bacteria. This page follows what the Galveston Island Beach Patrol and county officials publish.
What the flags meanGalveston beach · Photo: Aaron Tinoco / Unsplash · Credits
Do these four checks on the day you swim. The flag shows the surf and currents, Texas Beach Watch shows the bacteria results, and a tower with a guard in it means someone is watching the water.
The Beach Patrol puts up flags and signs every day on Seawall Boulevard at 61st, 53rd, 37th, 29th and 10th Street. In summer, every tower with a lifeguard flies them too. So do East Beach, Stewart Beach and the West End pocket parks during opening hours.
Sign up with the Beach Patrol and it sends you the day's flags and advisories by email or text.
A rip current is a narrow, fast channel of water flowing away from the beach. It pulls you out to sea but doesn't pull you under. Rips usually form at gaps in sandbars and next to groins, jetties and piers, and they get stronger as the waves grow.
Often you can't see any of these. Polarized sunglasses help. The safest place to swim is in front of a lifeguard tower that has a guard in it right now. Stewart Beach and East Beach have lifeguards, and during the beach season the Beach Patrol staffs 24 towers from East Beach to 61st Street, though not every tower has a guard all day. Travelling with young children? Stay near one of them. Ask a lifeguard where it's safest to swim.
At the east tip, next to East Beach, the bottom drops off fast into the Houston–Galveston Ship Channel, and the wakes of passing ships can set off sudden currents. At the west tip, San Luis Pass has strong tidal currents, shifting sand and deep channels that catch swimmers and people wading out to fish. The Beach Patrol prohibits going into the water at both. At San Luis Pass, swimming or wading in the restricted area can cost you a fine of up to $500.
Sources: Beach Patrol safety tips, Brazoria County: San Luis Pass rules. More beach rules: Galveston beaches compared.
The brownish green comes from plankton and from silt that rivers such as the Brazos and the Mississippi carry to the coast. The color is natural, and it says nothing about whether the water meets bacteria standards. On stormy days the brown is stirred-up sand. The water turns clearer, sometimes blue, after several days of light or offshore winds, once the sediment settles.
For bacteria, look up the station nearest your beach on Texas Beach Watch and check the date of its last sample. This Texas General Land Office program tests for Enterococcus, a bacterium that points to sewage or storm runoff. It samples weekly from March to October and every two weeks for the rest of the year. When an advisory is out, stay out of the water: no swimming, wading or surfing. You can still use the beach unless local authorities have closed it. A clean result only covers that one indicator, not every germ.
From late spring into summer, brown sargassum can pile up on the sand (water temperatures and seasons month by month: best time to visit). It drifts in from the Atlantic, and young sea turtles and fish shelter in it. County rules allow crews to remove it only once a pile is at least 8 feet wide and 6 inches high, so expect some on the beach. NOAA's Sargassum Inundation Risk tool shows the daily risk for coasts near drifting sargassum. It isn't a forecast of when seaweed will wash up.
Sources: Visit Galveston: beach conditions, water color, seaweed and sand, water color explained, Texas Beach Watch FAQ, NOAA AOML
Under a red flag, children stay at the water's edge. On green and yellow days, these three rules still apply.
Source: CDC: drowning prevention
Sources: Beach Patrol Texas-specific hazards; American Heart Association and Red Cross first aid guidelines 2024; American Academy of Dermatology; National Weather Service; CDC: Vibrio.
August has the warmest water and January the coldest. From June to August the average is above 84 °F. The figures are NOAA's long-term monthly averages for the station at the entrance to Galveston Bay.
Source: NOAA NCEI Coastal Water Temperature Guide, station Galveston Bay Entrance, North Jetty
| Month | °F | °C |
|---|---|---|
| Jan | 55.8 °F | 13.2 °C |
| Feb | 57.8 °F | 14.3 °C |
| Mar | 64.5 °F | 18.1 °C |
| Apr | 71.9 °F | 22.2 °C |
| May | 78.4 °F | 25.8 °C |
| Jun | 84.4 °F | 29.1 °C |
| Jul | 85.9 °F | 29.9 °C |
| Aug | 86.8 °F | 30.4 °C |
| Sep | 83.6 °F | 28.7 °C |
| Oct | 77.0 °F | 25.0 °C |
| Nov | 67.6 °F | 19.8 °C |
| Dec | 59.9 °F | 15.5 °C |
