Georgia Coast
Darien Water Temperature
The Altamaha delta — shrimp boats, black water, and marsh in every direction.
That is about 8°F warmer than average for this time of year, and cooling over the last two weeks. The October average here is 74°F.
Updated Saturday, October 3 — sea-surface temperature modeled for Darien 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.
Darien 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 | 57–70°F | Bracing |
| April | 71°F | 66–77°F | Cool but comfortable |
| May | 78°F | 72–83°F | Warm |
| June | 83°F | 74–88°F | Very warm |
| July | 87°F | 85–90°F | Very warm |
| August | 86°F | 81–90°F | Very warm |
| September | 82°F | 78–86°F | Very warm |
| Octobernow | 74°F | 69–82°F | Cool but comfortable |
| 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 Darien
Darien sits on the Altamaha delta, where one of the largest free-flowing river systems on the East Coast fans out into a maze of creeks, sounds, and spartina before it reaches the ocean. That freshwater push makes this stretch different from the rest of the Georgia coast: striped bass live in the river above the salt line, redfish and trout work the brackish creeks and oyster bars below it, and the salt wedge slides up and down with rainfall as much as with tide. The river's water trail runs down through swamp forest to the coast and is one of the better multi-day paddles in the Southeast. Shrimp boats still work out of the docks here, and the town has changed less than most of this coast.
the Altamaha delta & Doboy 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 Darien; 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 Darien right now?
- The water at Darien is currently about 82°F (28°C). The October average here is 74°F.
- Is the water warm enough to swim at Darien in October?
- October averages 74°F at Darien, which most people would call cool but comfortable. Refreshing rather than cold — comfortable once you're past the first minute.
- When is the water warmest at Darien?
- July is the warmest month on average at 87°F, and January the coolest at 54°F. 5 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.