August weather forecast
Charleston, SC

Trees along both sides of a street in Charleston, South Carolina
Trees along both sides of a street in Charleston, South Carolina

Weather in August

August, the last month of the summer in Charleston, is another hot month, with temperature in the range of an average low of 76.8°F (24.9°C) and an average high of 87.4°F (30.8°C).

Temperature

In Charleston, the average high-temperature in August is practically the same as in July - a still tropical 87.4°F (30.8°C). In August, in Charleston, South Carolina, the average low-temperature is 76.8°F (24.9°C).

Heat index

The average heat index in August is computed to be a very hot 102°F (38.9°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'felt air temperature', 'feels like', or 'real feel', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. Additional factors like clothing, wind, pregnancy, and activity influence one's weather impression. 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.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. If the body can not disperse the excessive heat and body temperature reaches conditions of hyperthermia, above 99.5°F (37.5°C) to 100.9°F (38.3°C), thermal conditions are potentially life-threatening.

Humidity

In Charleston, South Carolina, the average relative humidity in August is 76%.

Rainfall

August is the month with the most rainfall. Rain falls for 24.8 days and accumulates 7.13" (181mm) of precipitation.

Snowfall

In Charleston, snow does not fall in February through November.

Ocean temperature

The month with the warmest seawater is August, with an average ocean temperature of 83.5°F (28.6°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

In August, the average length of the day in Charleston is 13h and 19min.
On the first day of the month, sunrise is at 6:33 am and sunset at 8:18 pm. On the last day of August, sunrise is at 6:53 am and sunset at 7:46 pm EDT.

Sunshine

In August, the average sunshine in Charleston is 10.8h.

UV index

The months with the highest UV index in Charleston, South Carolina, are May through August, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high health risk from unsafe exposure to UV radiation for the ordinary person.
Note: In August, the average maximum UV index of 7 translate into the following recommendations:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. 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 August in Charleston?

In Charleston, in August, the average high-temperature is 87.4°F (30.8°C), and the average low-temperature is 76.8°F (24.9°C). The average heat index (a.k.a. 'feels like', 'apparent temperature'), which combines air temperature and relative humidity, in August is computed to be 102°F (38.9°C).

What is the average humidity in August in Charleston?

The average relative humidity in August is 76%.

What is the rainiest month in Charleston?

August is the month with the most rainfall in Charleston, South Carolina. Rain falls for 24.8 days and accumulates 7.13" (181mm) of precipitation.

How many days does it rain in August in Charleston?

In Charleston, during August, the rain falls for 24.8 days and regularly aggregates up to 7.13" (181mm) of precipitation.

When it does not snow in Charleston?

February through November are months without snowfall in Charleston.

When is the ocean warmest in Charleston?

August is the month with the warmest seawater in Charleston, South Carolina, with an average ocean temperature of 83.5°F (28.6°C).

How warm is the water in August in Charleston?

In Charleston, the average seawater temperature in August is 83.5°F (28.6°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 Charleston have in August?

The average day length in August is 13h and 19min.

When is the sunrise / sunset in August in Charleston?

On the first day of August in Charleston, South Carolina, sunrise is at 6:33 am and sunset at 8:18 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 7:46 pm EDT.

How long on average sun shines in August in Charleston?

In Charleston, the average sunshine duration in August is 10.8h.

What are the months with the highest UV index in Charleston?

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

What is the UV index intensity in August in Charleston?

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

Average temperature in August
Charleston, SC

Average temperature in August - Charleston, SC
  • Average high temperature in August: 87.4°F

The warmest month (with the highest average high temperature) is July (88.2°F).
The month with the lowest average high temperature is January (57°F).

  • Average low temperature in August: 76.8°F

The month with the highest average low temperature is July (77.4°F).
The coldest month (with the lowest average low temperature) is January (44.4°F).

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Average pressure in August
Charleston, SC

Average pressure in August - Charleston, SC
  • Average pressure in August: 29.99"Hg

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

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Average wind speed in August
Charleston, SC

Average wind speed in August - Charleston, SC
  • Average wind speed in August: 7.5mph

The windiest month (with the highest average wind speed) is April (9.4mph).
The calmest month (with the lowest average wind speed) is August (7.5mph).

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Average humidity in August
Charleston, SC

Average humidity in August - Charleston, SC
  • Average humidity in August: 76%

The month with the highest relative humidity is December (78%).
The months with the lowest relative humidity are January and March (73%).

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Average rainfall in August
Charleston, SC

Average rainfall in August - Charleston, SC
  • Average rainfall in August: 7.13"

The wettest month (with the highest rainfall) is August (7.13").
The driest month (with the least rainfall) is January (1.42").

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Average rainfall days in August
Charleston, SC

Average rainfall days in August - Charleston, SC
  • Average rainfall days in August: 24.8 days

The month with the highest number of rainy days is August (24.8 days).
The month with the least rainy days is November (8.7 days).

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Average snowfall in August
Charleston, SC

Average snowfall in August - Charleston, SC
  • Average snowfall in August: 0"

The month with the highest snowfall is January (0.12").
The months with the least snowfall are February, March, April, May, June, July, August, September, October and November (0").

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Average snowfall days in August
Charleston, SC

Average snowfall days in August - Charleston, SC
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is January (0.4 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October and November (0 days).

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Average sea temperature in August
Charleston, SC

Average sea temperature in August - Charleston, SC
  • Average sea temperature in August: 83.5°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 (61.9°F).

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Average daylight in August /
Average sunshine in August
Charleston, SC

Average daylight in August / Average sunshine in August - Charleston, SC
  • Average daylight in August: 13h and 19min

The month with the longest days is June (Average daylight: 14h and 17min).
The month with the shortest days is December (Average daylight: 10h and 2min).

  • Average sunshine in August: 10h 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 42min).

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Average sunshine days in August
Charleston, SC

Average sunshine days in August - Charleston, SC
  • Average sunshine days in August: 3.8 days

The month with the most sunshine days is January (19.3 days).
The month with the least sunshine days is August (3.8 days).

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Average UV index in August
Charleston, SC

Average UV index in August - Charleston, SC
  • Average UV index in August: 7

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 August
Charleston, SC

Average cloud cover in August - Charleston, SC
  • Average cloud cover in August: 28

The months with the most cloud cover are February and December (Cloud cover 39).
The months with the least cloud cover are June and July (Cloud cover 26).

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Average visibility in August
Charleston, SC

Average visibility in August - Charleston, SC
  • Average visibility in August: 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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