September weather forecast
Hilton Head Island, SC

Tall iconic lighthouse seen in a great night view over downtown Hilton Head Island, South Carolina
Tall iconic lighthouse seen in a great night view over downtown Hilton Head Island, South Carolina

Weather in September

The first month of the autumn, September, is still a warm month in Hilton Head Island, South Carolina, with an average temperature varying between 74.1°F (23.4°C) and 83.3°F (28.5°C).

Temperature

In Hilton Head Island, the average high-temperature in September is almost the same as in August - a moderately hot 83.3°F (28.5°C). The average low-temperature, in September, is 74.1°F (23.4°C).

Heat index

The average heat index in September is evaluated at a tropical 89.6°F (32°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'real feel', 'felt air temperature', or 'feels like', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (differences in body mass, height, and shape, clothing, wind). Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.

Humidity

The average relative humidity in September is 75%.

Rainfall

In September, in Hilton Head Island, the rain falls for 17.9 days. Throughout September, 3.78" (96mm) of precipitation is accumulated. In Hilton Head Island, during the entire year, the rain falls for 175.3 days and collects up to 32.28" (820mm) of precipitation.

Snowfall

February through December are months without snowfall in Hilton Head Island.

Ocean temperature

In September, the average ocean temperature in Hilton Head Island is 81.7°F (27.6°C).
Note: For any water activity, surface water temperatures between 77°F (25°C) and 84.2°F (29°C) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

The average length of the day in September is 12h and 21min.
On the first day of the month, sunrise is at 6:58 am and sunset at 7:47 pm. On the last day of September, in Hilton Head Island, sunrise is at 7:16 am and sunset at 7:09 pm EDT.

Sunshine

In September, the average sunshine in Hilton Head Island is 8.8h.

UV index

The average daily maximum UV index in September in Hilton Head Island is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 6 in September transform into the following instructions:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.
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FAQ

What is the temperature in September in Hilton Head Island?

In September, in Hilton Head Island, South Carolina, the average high-temperature is 83.3°F (28.5°C), and the average low-temperature is 74.1°F (23.4°C). in September, the average heat index (a.k.a. 'feels like', 'real feel'), which calculates the temperature value influenced by the moisture in the air, is evaluated at 89.6°F (32°C).

What is the average humidity in September in Hilton Head Island?

In Hilton Head Island, South Carolina, the average relative humidity in September is 75%.

How many days does it rain in September in Hilton Head Island?

In Hilton Head Island, in September, during 17.9 rainfall days, 3.78" (96mm) of precipitation is typically accumulated.

When it does not snow in Hilton Head Island?

In Hilton Head Island, snow does not fall in February through December.

How warm is the water in September in Hilton Head Island?

In Hilton Head Island, South Carolina, in September, the average water temperature is 81.7°F (27.6°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 Hilton Head Island have in September?

The average day length in September in Hilton Head Island is 12h and 21min.

What time are sunrise and sunset in September in Hilton Head Island?

On the first day of September in Hilton Head Island, South Carolina, sunrise is at 6:58 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 7:09 pm EDT.

How many hours of sunshine does Hilton Head Island have in September?

The average sunshine duration in September in Hilton Head Island, South Carolina, is 8.8h.

What is the UV index intensity in September in Hilton Head Island?

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

Average temperature in September
Hilton Head Island, SC

Average temperature in September - Hilton Head Island, SC
  • Average high temperature in September: 83.3°F

The warmest month (with the highest average high temperature) is July (87.6°F).
The month with the lowest average high temperature is January (57.4°F).

  • Average low temperature in September: 74.1°F

The month with the highest average low temperature is July (77.9°F).
The coldest month (with the lowest average low temperature) is January (46°F).

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Average pressure in September
Hilton Head Island, SC

Average pressure in September - Hilton Head Island, SC
  • Average pressure in September: 29.99"Hg

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

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Average wind speed in September
Hilton Head Island, SC

Average wind speed in September - Hilton Head Island, SC
  • Average wind speed in September: 8.5mph

The windiest months (with the highest average wind speed) are January, March and April (9.6mph).
The calmest month (with the lowest average wind speed) is August (7.8mph).

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Average humidity in September
Hilton Head Island, SC

Average humidity in September - Hilton Head Island, SC
  • Average humidity in September: 75%

The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is January (72%).

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Average rainfall in September
Hilton Head Island, SC

Average rainfall in September - Hilton Head Island, SC
  • Average rainfall in September: 3.78"

The wettest month (with the highest rainfall) is August (6.06").
The driest month (with the least rainfall) is January (1.02").

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Average rainfall days in September
Hilton Head Island, SC

Average rainfall days in September - Hilton Head Island, SC
  • Average rainfall days in September: 17.9 days

The month with the highest number of rainy days is August (25 days).
The month with the least rainy days is January (8.3 days).

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Average snowfall in September
Hilton Head Island, SC

Average snowfall in September - Hilton Head Island, SC
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.04").
The months with the least snowfall are February, March, April, May, June, July, August, September, October, November and December (0").

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Average snowfall days in September
Hilton Head Island, SC

Average snowfall days in September - Hilton Head Island, SC
  • Average snowfall days in September: 0 days

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

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Average sea temperature in September
Hilton Head Island, SC

Average sea temperature in September - Hilton Head Island, SC
  • Average sea temperature in September: 81.8°F

The best month for swimming (with the highest average sea temperature) is August (83.5°F).
The coldest month (with the lowest average sea temperature) is February (57.5°F).

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Average daylight in September /
Average sunshine in September
Hilton Head Island, SC

Average daylight in September / Average sunshine in September - Hilton Head Island, SC
  • Average daylight in September: 12h and 21min

The month with the longest days is June (Average daylight: 14h and 14min).
The month with the shortest days is December (Average daylight: 10h and 5min).

  • Average sunshine in September: 8h and 48min

The months with the most sunshine are June and July (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).

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Average sunshine days in September
Hilton Head Island, SC

Average sunshine days in September - Hilton Head Island, SC
  • Average sunshine days in September: 8.3 days

The month with the most sunshine days is January (20.3 days).
The month with the least sunshine days is August (2.8 days).

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Average UV index in September
Hilton Head Island, SC

Average UV index in September - Hilton Head Island, SC
  • Average UV index in September: 6

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

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Average cloud cover in September
Hilton Head Island, SC

Average cloud cover in September - Hilton Head Island, SC
  • Average cloud cover in September: 28

The months with the most cloud cover are February and December (Cloud cover 38).
The months with the least cloud cover are June and July (Cloud cover 25).

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Average visibility in September
Hilton Head Island, SC

Average visibility in September - Hilton Head Island, SC
  • 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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