December is a popular month to ask about Sullivan's Island because conditions can shift week to week along this coast. Expect the water near 16.0°C, with daily variation from wind, tides and recent storms. We refresh the live value from Open-Meteo Marine every hour, so the headline above always reflects the current state of the Atlantic Ocean.
Sullivan's Island sea temperature in December — averages 16.0°C
The sea at Sullivan's Island in United States averages 16.0°C during December, based on long-run climatology for the Atlantic Ocean. Use the live reading below for today's actual water and the monthly grid to compare with the rest of the year.
Average sea · December
16.0°C
mild · Fair
Live water now
…
Recommended wetsuit
3/2mm fullsuit
At 16.0°C a 3/2mm fullsuit is the standard wetsuit for surfing and watersports.
Monthly comparison
Yes, but expect a fresh dip · Sullivan's Island
Can you swim at Sullivan's Island in June? — 27.0°C water27.0°CCan you swim at Sullivan's Island in July? — 29.0°C water29.0°CCan you swim at Sullivan's Island in August? — 29.0°C water29.0°CCan you swim at Sullivan's Island in September? — 27.0°C water27.0°CCan you swim at Sullivan's Island in October? — 23.0°C water23.0°CCan you swim at Sullivan's Island in November? — 19.0°C water19.0°C
Frequently asked questions
What is the average sea temperature at Sullivan's Island in December?
Sullivan's Island averages 16.0°C in December, based on long-run climatology for the Atlantic Ocean.
Is the sea warm enough to swim at Sullivan's Island in December?
It is swimmable but fresh; confident swimmers will be fine without a wetsuit.
Do I need a wetsuit at Sullivan's Island in December?
A 2 mm shorty is comfortable for sessions over 30 minutes.