December weather forecastSaint Simons Island, GA

A long pier with a large shed on the St. Simons Island, Georgia, the rocks and seawater and colorful sunset clouds in the sky above

December

Weather in December

December sees the onset of winter on Saint Simons Island. The weather grows colder, contrasted with the mild November climate. Rainfall remains moderate, and the daylight hours continue to shorten. The most noticeable feature of December on Saint Simons Island is the sea temperature that drops to 63 degrees F, substantially cooler than November. While not as bustling as the summer months, December offers a tranquil, festive vibe, making it a unique time to experience the Island's charm.

Temperature

The onset of December notes an average high-temperature of a comfortable 64.4°F (18°C), subtly shifted from November's 68.9°F (20.5°C). Saint Simons Island records an average nighttime low-temperature of 52.9°F (11.6°C) throughout December.

Humidity

August and December, with an average relative humidity of 78%, are the most humid months.

Rainfall

In Saint Simons Island, in December, it is raining for 9.5 days, with typically 1.02" (26mm) of accumulated precipitation. Throughout the year, there are 163.3 rainfall days, and 20.43" (519mm) of precipitation is accumulated.

Snowfall

February and December are months with snowfall. The months with the most snowfall days are February and December, with an average of 0.1 snowfall days.

Ocean temperature

In Saint Simons Island, in December, the average water temperature is 63°F (17.2°C).
Note: Most people do not enjoy swimming in water of 63°F (17.2°C). Breathing control becomes harder as the temperature descends from 69.8°F (21°C) to 59°F (15°C).

Daylight

December has the shortest days of the year, with an average of 10h and 12min of daylight.
On the first day of the month, sunrise is at 7:06 am and sunset at 5:22 pm. On the last day of December, sunrise is at 7:23 am and sunset at 5:33 pm EST.

Sunshine

With an average of 5.8h of sunshine, December has the least sunshine of the year.

UV index

In Saint Simons Island, the average daily maximum UV index in December is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In December, the maximum UV index of 4 translates into these guidelines:
Guard yourself - An obligation to protect skin and eyes from harm exists. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.

Updated: Jul 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

An average high-temperature, in December, in Saint Simons Island, is 64.4°F (18°C) and the average low-temperature is 52.9°F (11.6°C). In September, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which calculates the temperature value influenced by the moisture in the air, is calculated to be 95°F (35°C).

The months with the highest humidity in Saint Simons Island are August and December, with an average relative humidity of 78%.

In December, the average relative humidity is 78%.

In Saint Simons Island, in December, during 9.5 rainfall days, 1.02" (26mm) of precipitation is typically accumulated.

The months with the most snowfall days are February and December, with an average of 0.1 snowfall days.

December is the first month it typically snows. Throughout December, there are 0.1 snowfall days.

In December, the average ocean temperature is 63°F (17.2°C). For swimming, a surface water temperature of 63°F (17.2°C) is not enjoyable for the majority. It is not considered safe, as controlling breathing becomes progressively more difficult as water temperature decreases below 69.8°F (21°C).

The month with the shortest days is December, with an average of 10h and 12min of daylight.

In December, the average day length in Saint Simons Island is 10h and 10min.

In December, on the first day of the month, sunrise is at 7:06 am and sunset at 5:22 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 5:33 pm EST.

The month with the least sunshine is December, with an average of 5.8h of sunshine.

In Saint Simons Island, the average sunshine duration in December is 5.8h.

In December, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium health risk from exposure to the Sun's UV radiation.

Today

Tomorrow

Long-term

Year J F M A M J J A S O N December

Nov

December

Jan

Average high temperature

68.9°F

64.4°F

60.4°F

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

9.3mph

9.2mph

9.4mph

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

8.6

9.5

8.2

Average snowfall days

0.1

Average sea temperature

Average daylight

Average sunshine

Average sunshine days

17.8

19.5

19.8

Average UV index

Average cloud cover

Average visibility

Average temperature in December
Saint Simons Island, GA

Average high temperature in December: 64.4°F

The warmest month (with the highest average high temperature) is July (88.7°F).
The month with the lowest average high temperature is January (60.4°F).

Average low temperature in December: 52.9°F

The month with the highest average low temperature is August (77.4°F).
The coldest month (with the lowest average low temperature) is January (47.7°F).

Average pressure in December
Saint Simons Island, GA

Average pressure in December: 30.12"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.98"Hg).

Average wind speed in December
Saint Simons Island, GA

Average wind speed in December: 8.6mph

The windiest months (with the highest average wind speed) are January and April (8.8mph).
The calmest month (with the lowest average wind speed) is August (6.9mph).

Average humidity in December
Saint Simons Island, GA

Average humidity in December: 78%

The months with the highest relative humidity are August and December (78%).
The month with the lowest relative humidity is March (72%).

Average rainfall in December
Saint Simons Island, GA

Average rainfall in December: 1.02"

The wettest month (with the highest rainfall) is August (3.43").
The driest month (with the least rainfall) is January (0.59").

Average rainfall days in December
Saint Simons Island, GA

Average rainfall days in December: 9.5 days

The month with the highest number of rainy days is August (23.3 days).
The month with the least rainy days is January (8.2 days).

Average snowfall days in December
Saint Simons Island, GA

Average snowfall days in December: 0.1 days

The months with the highest number of snowfall days are February and December (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October and November (0 days).

Average sea temperature in December
Saint Simons Island, GA

Average sea temperature in December: 63°F

The best month for swimming (with the highest average sea temperature) is August (83.4°F).
The coldest month (with the lowest average sea temperature) is February (58.5°F).

Average daylight in December /
Average sunshine in December
Saint Simons Island, GA

Average daylight in December: 10h and 12min

The month with the longest days is June (Average daylight: 14h and 6min).
The month with the shortest days is December (Average daylight: 10h and 12min).

Average sunshine in December: 5h and 48min

The month with the most sunshine is July (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

Average sunshine days in December
Saint Simons Island, GA

Average sunshine days in December: 19.5 days

The month with the most sunshine days is March (20.1 days).
The month with the least sunshine days is August (4.2 days).

Average UV index in December
Saint Simons Island, GA

Average UV index in December: 4

The months with the highest UV index are May, June, July, August and September (UV index 7).
The month with the lowest UV index is January (UV index 3).

Average cloud cover in December
Saint Simons Island, GA

Average cloud cover in December: 38

The months with the most cloud cover are February and December (Cloud cover 38).
The months with the least cloud cover are April, May, June and July (Cloud cover 27).

Average visibility in December
Saint Simons Island, GA

Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).