Georgia Coast
Brunswick Water Temperature
The Marshes of Glynn, two big sounds, and a working shrimp port.
That is about 7°F warmer than average for this time of year, and cooling over the last two weeks. The October average here is 75°F.
Updated Saturday, October 3 — sea-surface temperature modeled for Brunswick by Open-Meteo.
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.
Brunswick 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 | 54°F | 48–58°F | Cold |
| February | 58°F | 54–67°F | Cold |
| March | 64°F | 57–71°F | Bracing |
| April | 71°F | 66–77°F | Cool but comfortable |
| May | 78°F | 72–84°F | Warm |
| June | 83°F | 75–88°F | Very warm |
| July | 87°F | 85–90°F | Very warm |
| August | 87°F | 81–90°F | Very warm |
| September | 82°F | 79–86°F | Very warm |
| Octobernow | 75°F | 69–82°F | Warm |
| November | 68°F | 61–75°F | Cool but comfortable |
| December | 59°F | 56–64°F | Cold |
Warmest on average in July at 87°F; coolest in January at 54°F.
The water at Brunswick
Brunswick is a port town wrapped in the marsh Sidney Lanier wrote about, with the Turtle and Brunswick rivers feeding St. Simons Sound and Altamaha Sound just to the north. Fishing here is sound-and-creek work: redfish and trout along the grass and the oyster rakes, black drum and sheepshead around bridge pilings and dock structure, and tripletail floating near markers and buoys from spring into summer. Seven- and eight-foot tides make the sounds run hard, and where two of them meet you get rips that stack bait. Those same creeks make for good paddling and better birding, and the shrimp docks still put boats out every season. When it blows from the northeast, duck into the back creeks and let the sounds settle.
St. Simons Sound & the marsh rivers
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 Brunswick; 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 Brunswick right now?
- The water at Brunswick is currently about 82°F (28°C). The October average here is 75°F.
- Is the water warm enough to swim at Brunswick in October?
- October averages 75°F at Brunswick, 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 Brunswick?
- July is the warmest month on average at 87°F, and January the coolest at 54°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.