July weather forecast
Charleston, SC

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

Weather in July

July is a crucial month for Charleston, marking the zenith of summer. The weather is typically hot and humid, with some rainfall offering brief respite from the neck-cranking heat. Standing at its peak, July signals a slight uptick in relative humidity at 75%. The hottest days of the year can be expected during this time as Charleston experiences its highest mean temperatures.

Temperature

Charleston's warmest month, July, generally records average temperatures ranging from a high of 88.2°F (31.2°C) to a low of 77.4°F (25.2°C).

Heat index

July's average heat index is calculated to be a blistering 104°F (40°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
One should consider that heat index numbers are for shaded settings and light wind. The heat index values could be amplified by up to 15 Fahrenheit (8 Celsius) degrees in direct sunlight.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is achieved by amalgamating air temperature with the relative humidity readings. Factors such as metabolic variation, pregnancy, and physical activity play a role in one's impression of weather. Realize that direct exposure to sunlight can augment the felt heat, leading to a potential increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. Children often overlook the need for breaks and fluid intake. Thirst is a late-stage sign of dehydration - hence, it is necessary to stay hydrated, especially during extended periods of physical activities.
Perspiration and the resultant sweat evaporation are the body's natural thermostat, helping regulate temperature. An upsurge in relative humidity affects normal body cooling mechanisms by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. When body temperature rises due to an imbalance in heat gain, there's a potential for dehydration and overheating.

Humidity

In Charleston, the average relative humidity in July is 75%.

Rainfall

In July, in Charleston, the rain falls for 23.3 days. Throughout July, 4.72" (120mm) of precipitation is accumulated. Throughout the year, in Charleston, there are 178.9 rainfall days, and 41.93" (1065mm) of precipitation is accumulated.

Snowfall

February through November are months without snowfall in Charleston.

Ocean temperature

In Charleston, South Carolina, the average seawater temperature in July is 82.9°F (28.3°C).
Note: Water temperature ranging from 77°F (25°C) to 84.2°F (29°C) is seen as very warm and delightful by everyone. During these temperatures, water activities become enjoyable, without causing discomfort for extended periods.

Daylight

In Charleston, the average length of the day in July is 14h and 4min.
On the first day of July, sunrise is at 6:15 am and sunset at 8:31 pm. On the last day of the month, sunrise is at 6:33 am and sunset at 8:18 pm EDT.

Sunshine

With an average of 11h of sunshine, July has the most sunshine of the year in Charleston, South Carolina.

UV index

The months with the highest UV index are May through August, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The maximum daily UV index of 7 in July interprets into the following recommendations:
Evade overexposure. Individuals with fair skin risk burning in under 20 minutes. Limit direct sun exposure especially between 10 a.m. and 4 p.m., when UV radiation is at its peak. However, keep in mind that shade structures may not provide full sun protection. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Caution! The mirror effect of sand and water ups the UV radiation strength.
Updated: Feb 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the hottest in Charleston?

Charleston's July weather reaches an average high of 88.2°F (31.2°C) and an average low of 77.4°F (25.2°C), making it the warmest month.

How hot does it get in Charleston in July?

An average high-temperature, in July, in Charleston, is 88.2°F (31.2°C) and the average low-temperature is 77.4°F (25.2°C). In July, 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 104°F (40°C).

What is the average humidity in July in Charleston?

In July, the average relative humidity in Charleston is 75%.

How much does it rain in Charleston in July?

In Charleston, in July, during 23.3 rainfall days, 4.72" (120mm) of precipitation is typically accumulated.

When it does not snow in Charleston?

February through November are months without snowfall.

What is the ocean temperature in July in Charleston?

In July, the average ocean temperature in Charleston is 82.9°F (28.3°C). 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.

What is the average length of the day in July in Charleston?

The average day length in July in Charleston is 14h and 4min.

When is the sunrise / sunset in July in Charleston?

In July, on the first day of the month, sunrise is at 6:15 am and sunset at 8:31 pm. On the last day of the month, in Charleston, sunrise is at 6:33 am and sunset at 8:18 pm EDT.

What month has the most sunshine in Charleston?

July has the most sunshine of the year, with an average of 11h of sunshine.

How long on average sun shines in July in Charleston?

In Charleston, the average sunshine duration in July is 11h.

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

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

What is the UV index reading in July in Charleston?

The average daily maximum UV index in July in Charleston is 7. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in July
Charleston, SC

Average temperature in July - Charleston, SC
  • Average high temperature in July: 88.2°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 July: 77.4°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).

Average pressure in July
Charleston, SC

Average pressure in July - Charleston, SC
  • Average pressure in July: 30"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).

Average wind speed in July
Charleston, SC

Average wind speed in July - Charleston, SC
  • Average wind speed in July: 8.1mph

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).

Average humidity in July
Charleston, SC

Average humidity in July - Charleston, SC
  • Average humidity in July: 75%

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

Average rainfall in July
Charleston, SC

Average rainfall in July - Charleston, SC
  • Average rainfall in July: 4.72"

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

Average rainfall days in July
Charleston, SC

Average rainfall days in July - Charleston, SC
  • Average rainfall days in July: 23.3 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).

Average snowfall in July
Charleston, SC

Average snowfall in July - Charleston, SC
  • Average snowfall in July: 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").

Average snowfall days in July
Charleston, SC

Average snowfall days in July - Charleston, SC
  • Average snowfall days in July: 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).

Average sea temperature in July
Charleston, SC

Average sea temperature in July - Charleston, SC
  • Average sea temperature in July: 83°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).

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

Average daylight in July / Average sunshine in July - Charleston, SC
  • Average daylight in July: 14h and 1min

The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in July: 11h and 0min

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).

Average sunshine days in July
Charleston, SC

Average sunshine days in July - Charleston, SC
  • Average sunshine days in July: 5.7 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).

Average UV index in July
Charleston, SC

Average UV index in July - Charleston, SC
  • Average UV index in July: 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).

Average cloud cover in July
Charleston, SC

Average cloud cover in July - Charleston, SC
  • Average cloud cover in July: 26

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).

Average visibility in July
Charleston, SC

Average visibility in July - Charleston, SC
  • Average visibility in July: 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).

Charleston, South Carolina, USA

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