Forgotten Coast
St. George Island Water Temperature
Undeveloped Gulf beach, Sikes Cut, and St. George Sound.
That is about 2°F warmer than average for this time of year, and holding steady over the last two weeks. The September average here is 84°F.
Updated Monday, September 21 — sea-surface temperature modeled for St. George Island 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.
St. George Island 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 | 58°F | 51–64°F | Cold |
| February | 62°F | 56–70°F | Bracing |
| March | 68°F | 63–73°F | Cool but comfortable |
| April | 73°F | 69–79°F | Cool but comfortable |
| May | 80°F | 73–85°F | Warm |
| June | 85°F | 79–89°F | Very warm |
| July | 88°F | 85–89°F | Bath water |
| August | 88°F | 85–91°F | Bath water |
| Septembernow | 84°F | 81–88°F | Very warm |
| October | 77°F | 71–83°F | Warm |
| November | 70°F | 64–77°F | Cool but comfortable |
| December | 62°F | 56–67°F | Bracing |
Warmest on average in July at 88°F; coolest in January at 58°F.
The water at St. George Island
St. George Island is 28 miles of barrier island with a state park covering the entire east end — some of the most undeveloped beach left in Florida. Pompano and whiting work the surf, Sikes Cut on the west end concentrates everything moving between the bay and the Gulf, and the sound side offers protected grass and oyster for trout and redfish when the Gulf is rough.
Gulf beaches & St. George Sound
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 St. George Island; 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 St. George Island right now?
- The water at St. George Island is currently about 86°F (30°C). The September average here is 84°F.
- Is the water warm enough to swim at St. George Island in September?
- September averages 84°F at St. George Island, which most people would call very warm. Bath-warm. Pleasant, though it stops being much relief from the heat of the day.
- When is the water warmest at St. George Island?
- July is the warmest month on average at 88°F, and January the coolest at 58°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.