September weather forecast
Saint Simons Island, GA

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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
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

Weather in September

September brings a slow transition from the hot summer temperatures to a more comfortable fall climate on Saint Simons Island. It places a halt on the sequence of increasing rainfall from the summer, causing a reverse. The visible shortening of days and more moderate heat levels differ drastically from the conditions experienced in August. The main highlight of September is its reduced average rainfall of 2.8" (71mm), a significant decrease from August's high. It also signifies the nearing end of the main tourist season, offering a more relaxed atmosphere for visitors who linger.

Temperature

The shift into September in Saint Simons Island records an average high-temperature of a moderately hot 84.9°F (29.4°C), subtly varied from August's 88.3°F (31.3°C). In the month of September, Saint Simons Island experiences an average low-temperature of 74.3°F (23.5°C).

Heat index

During September, the heat index is calculated to be a fiery hot 95°F (35°C). Implement additional preventive actions, heat cramps and heat exhaustion are potential hazards. Heatstroke could follow prolonged activity.
Heat index data is primarily for areas with shade and subjected to light winds. The heat index might be elevated by 15 Fahrenheit (8 Celsius) degrees due to direct sun exposure.
Note: The heat index, also known as 'apparent temperature' or 'real feel', combines both the air temperature and the humidity level to give a perceived human temperature. The influence of weather is personal, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. Consider the sun's direct rays and their impact; they can potentially increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for babies and toddlers. Younglings frequently fail to recognize the requirement to rest and rehydrate. Thirst emerges late in dehydration - it is imperative to keep hydration levels high, particularly during extended physical exertions.
The human body keeps its cool primarily through perspiration, as this process enables sweat to evaporate, taking away the excess heat. When air moisture content is high, the cooling process through evaporation is not as efficient, leading to an ineffective body cooling process and a feeling of overheating. If heat absorption exceeds the body's cooling ability, body temperature can elevate, resulting in potential thermal illnesses.

Humidity

In Saint Simons Island, the average relative humidity in September is 77%.

Rainfall

In Saint Simons Island, during September, the rain falls for 19.2 days and regularly aggregates up to 2.8" (71mm) of precipitation. Throughout the year, there are 163.3 rainfall days, and 20.43" (519mm) of precipitation is accumulated.

Snowfall

January, March through November are months without snowfall in Saint Simons Island.

Ocean temperature

In September, the average ocean temperature in Saint Simons Island is 82.4°F (28°C).
Note: For activities in the water such as swimming or diving, temperatures from 77°F (25°C) to 84.2°F (29°C) are considered optimal for prolonged enjoyment without discomfort.

Daylight

The average length of the day in September in Saint Simons Island is 12h and 20min.
On the first day of September in Saint Simons Island, sunrise is at 7:02 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 7:11 pm EDT.

Sunshine

In Saint Simons Island, the average sunshine in September is 8.6h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index in Saint Simons Island. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: An average maximum UV index of 7 in September leads to these recommendations:
Dodge overexposure. Fair-skinned people can get singed in less than 20 minutes. Between 10 a.m. and 4 p.m., the Sun's UV radiation is at its peak. Limit your exposure to direct sunlight during these hours. Boost your sun resistance with garments that are densely woven yet spacious. Be on guard! The reflective nature of sand and water boosts UV exposure.
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Frequently asked questions

How hot does it get in Saint Simons Island in September?

An average high-temperature, in September, in Saint Simons Island, is 84.9°F (29.4°C) and the average low-temperature is 74.3°F (23.5°C). In September, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, is calculated to be 95°F (35°C).

What is the average humidity in September in Saint Simons Island?

In Saint Simons Island, Georgia, the average relative humidity in September is 77%.

How much does it rain in Saint Simons Island in September?

In Saint Simons Island, Georgia, in September, it is raining for 19.2 days, with typically 2.8" (71mm) of accumulated precipitation.

When it does not snow in Saint Simons Island?

January, March through November are months without snowfall in Saint Simons Island.

How warm is the water in September in Saint Simons Island?

In September, the average ocean temperature in Saint Simons Island is 82.4°F (28°C). For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

How many hours of daylight does Saint Simons Island have in September?

In September, the average day length in Saint Simons Island, Georgia, is 12h and 20min.

When is the sunrise / sunset in September in Saint Simons Island?

On the first day of September, sunrise is at 7:02 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 7:11 pm EDT.

How long on average sun shines in September in Saint Simons Island?

In September, the average sunshine duration in Saint Simons Island is 8.6h.

When is the highest UV index in Saint Simons Island?

May through September, with an average maximum UV index of 7, are months with the highest UV index.

What is the UV index reading in September in Saint Simons Island?

In September, the average daily maximum UV index is 7. A UV Index value of 6 to 7 symbolizes a high health threat from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Saint Simons Island, GA

Average temperature in September - Saint Simons Island, GA
  • Average high temperature in September: 84.9°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 September: 74.3°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).

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Average pressure in September
Saint Simons Island, GA

Average pressure in September - Saint Simons Island, GA
  • Average pressure in September: 29.98"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).

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Average wind speed in September
Saint Simons Island, GA

Average wind speed in September - Saint Simons Island, GA
  • Average wind speed in September: 7.6mph

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).

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Average humidity in September
Saint Simons Island, GA

Average humidity in September - Saint Simons Island, GA
  • Average humidity in September: 77%

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

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Average rainfall in September
Saint Simons Island, GA

Average rainfall in September - Saint Simons Island, GA
  • Average rainfall in September: 2.8"

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

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Average rainfall days in September
Saint Simons Island, GA

Average rainfall days in September - Saint Simons Island, GA
  • Average rainfall days in September: 19.2 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).

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Average snowfall days in September
Saint Simons Island, GA

Average snowfall days in September - Saint Simons Island, GA
  • Average snowfall days in September: 0 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).

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Average sea temperature in September
Saint Simons Island, GA

Average sea temperature in September - Saint Simons Island, GA
  • Average sea temperature in September: 82.4°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).

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

Average daylight in September / Average sunshine in September - Saint Simons Island, GA
  • Average daylight in September: 12h and 2min

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 September: 8h and 4min

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).

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Average sunshine days in September
Saint Simons Island, GA

Average sunshine days in September - Saint Simons Island, GA
  • Average sunshine days in September: 7.4 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).

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Average UV index in September
Saint Simons Island, GA

Average UV index in September - Saint Simons Island, GA
  • Average UV index in September: 7

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).

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Average cloud cover in September
Saint Simons Island, GA

Average cloud cover in September - Saint Simons Island, GA
  • Average cloud cover in September: 30

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).

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Average visibility in September
Saint Simons Island, GA

Average visibility in September - Saint Simons Island, GA
  • Average visibility in September: 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).

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Saint Simons Island, Georgia, USA

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