Texas Gulf Coast
Port Aransas Water Temperature
The Aransas Pass jetties, Mustang Island surf, and a genuine tarpon history.
That is about 6°F warmer than average for this time of year, and holding steady over the last two weeks. The October average here is 81°F.
Updated Friday, October 2 — sea-surface temperature modeled for Port Aransas by Open-Meteo.
Out in the open Gulf, NOAA buoy 42002 — 240 miles offshore — is reading 87°F. Deep water offshore runs cooler than the shallows in summer and warmer in winter, so it won't match the beach.
For swimming
Very warm
Bath-warm. Pleasant, though it stops being much relief from the heat of the day.
For fishing
Hot — fish the edges of the day
Early and late is the play. Through the middle of the day fish drop into deeper channels and passes where there's moving water and more oxygen.
The last two weeks
Daily average sea-surface temperature, °F.
Port Aransas water temperature by month
Averaged from 3 years of daily sea-surface temperature (2023–2025). The range column is the coolest and warmest daily average recorded in that month over the period — a guide to how much any given year can differ, not a record high and low.
| Month | Average | Range | Swimming |
|---|---|---|---|
| January | 60°F | 53–67°F | Bracing |
| February | 61°F | 58–66°F | Bracing |
| March | 67°F | 61–72°F | Bracing |
| April | 73°F | 70–78°F | Cool but comfortable |
| May | 80°F | 75–85°F | Warm |
| June | 85°F | 82–87°F | Very warm |
| July | 86°F | 84–87°F | Very warm |
| August | 87°F | 85–89°F | Very warm |
| September | 86°F | 82–88°F | Very warm |
| Octobernow | 81°F | 75–86°F | Warm |
| November | 74°F | 65–80°F | Cool but comfortable |
| December | 66°F | 60–73°F | Bracing |
Warmest on average in August at 87°F; coolest in January at 60°F.
The water at Port Aransas
Everything moving between the Gulf and the Coastal Bend runs through the Aransas Pass jetties at Port Aransas, and those two long granite arms are the most consistent land-based fishing on the middle coast. Trout, redfish, and flounder work the rocks and the Lydia Ann Channel behind them, and late summer brings tarpon back to the pass and the beachfront — a fishery this town was famous for long before it was a beach destination. Mustang Island's beach is drivable, surfable, and busy all summer, and the birding boardwalks in town put migrating songbirds and wading birds within a few feet. Ferry lines are the price of a good weekend, and the surf only fishes well when green water and a light wind show up together.
Mustang Island, the jetties & the ship channel
What moves the water temperature here
The Gulf shelf off this coast is shallow, which is why the water swings so much more between summer and winter than open ocean at the same latitude does. Shallow water heats fast and gives that heat up fast: a single strong winter cold front can pull the inshore bays several degrees down in a couple of days, while the beaches a mile offshore barely move. Wind direction matters too — a sustained offshore breeze can pull cooler water up from below and drop the beach temperature noticeably in a morning.
Inshore bays, canals and flats run warmer than the beach through the summer and colder through the winter, for the same reason. The reading above is for the open water at Port Aransas; expect the back bays to be a few degrees either side of it depending on the season.
Common questions
- What is the water temperature at Port Aransas right now?
- The water at Port Aransas is currently about 87°F (30°C). The October average here is 81°F.
- Is the water warm enough to swim at Port Aransas in October?
- October averages 81°F at Port Aransas, which most people would call warm. About as good as it gets — warm enough to stay in for hours without getting chilled.
- When is the water warmest at Port Aransas?
- August is the warmest month on average at 87°F, and January the coolest at 60°F. 6 months of the year average 75°F or above.
- Why does the water temperature change so quickly here?
- The Gulf shelf off this coast is shallow, so it heats and cools far faster than deep open ocean. A strong winter cold front can pull the inshore water down several degrees in a couple of days, and a sustained offshore wind can drop beach temperatures in a single morning by pulling cooler water up from below.