May 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 May

The last month of the spring, May, is a warm month in Charleston, South Carolina, with an average temperature ranging between min 68.2°F (20.1°C) and max 79.5°F (26.4°C).

Temperature

In May, the average high-temperature marginally rises from an agreeable 72.7°F (22.6°C) in April to a warm 79.5°F (26.4°C). In Charleston, South Carolina, in May, the average low-temperature is 68.2°F (20.1°C).

Humidity

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

Rainfall

In Charleston, in May, it is raining for 15.8 days, with typically 2.87" (73mm) of accumulated precipitation. In Charleston, during the entire year, the rain falls for 178.9 days and collects up to 41.93" (1065mm) of precipitation.

Snowfall

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

Ocean temperature

In Charleston, South Carolina, the average water temperature is 73°F (22.8°C).
Note: Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 73°F (22.8°C) water may be enjoyable. (FYI: The official water temperature required for the Olympic swimming competition is 77°F (25°C) to 82.4°F (28°C).)

Daylight

In May, the average length of the day is 13h and 52min.
On the first day of May in Charleston, South Carolina, sunrise is at 6:32 am and sunset at 8:01 pm. On the last day of the month, sunrise is at 6:12 am and sunset at 8:22 pm EDT.

Sunshine

In Charleston, South Carolina, the average sunshine in May is 10.5h.

UV index

May through August, with an average maximum UV index of 7, are months with the highest UV index in Charleston. A UV Index of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: The daily maximum UV index of 7 in May interpret into the following advice:
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. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. 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 average humidity in May in Charleston?

The average relative humidity in May in Charleston is 75%.

How much does it rain in Charleston in May?

In May, in Charleston, the rain falls for 15.8 days. Throughout May, 2.87" (73mm) of precipitation is accumulated.

When it does not snow in Charleston?

February through November are months without snowfall in Charleston, South Carolina.

How warm is the water in May in Charleston?

In May, the average ocean temperature is 73°F (22.8°C). A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 73°F (22.8°C) water.

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

In Charleston, South Carolina, the average day length in May is 13h and 52min.

What time are sunrise and sunset in May in Charleston?

In May, on the first day of the month, sunrise is at 6:32 am and sunset at 8:01 pm. On the last day of the month, sunrise is at 6:12 am and sunset at 8:22 pm EDT.

How many hours of sunshine does Charleston have in May?

In Charleston, South Carolina, the average sunshine duration in May is 10.5h.

What is the month 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 reading in May in Charleston?

In Charleston, the average daily maximum UV index in May is 7. A UV Index estimate of 6 to 7 represents a high hazard to health 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 May
Charleston, SC

Average temperature in May - Charleston, SC
  • Average high temperature in May: 79.5°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 May: 68.2°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 May
Charleston, SC

Average pressure in May - Charleston, SC
  • Average pressure in May: 30.03"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 May
Charleston, SC

Average wind speed in May - Charleston, SC
  • Average wind speed in May: 8.6mph

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 May
Charleston, SC

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

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 May
Charleston, SC

Average rainfall in May - Charleston, SC
  • Average rainfall in May: 2.87"

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 May
Charleston, SC

Average rainfall days in May - Charleston, SC
  • Average rainfall days in May: 15.8 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 May
Charleston, SC

Average snowfall in May - Charleston, SC
  • Average snowfall in May: 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 May
Charleston, SC

Average snowfall days in May - Charleston, SC
  • Average snowfall days in May: 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 May
Charleston, SC

Average sea temperature in May - Charleston, SC
  • Average sea temperature in May: 73°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 May /
Average sunshine in May
Charleston, SC

Average daylight in May / Average sunshine in May - Charleston, SC
  • Average daylight in May: 13h and 52min

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 May: 10h and 30min

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 May
Charleston, SC

Average sunshine days in May - Charleston, SC
  • Average sunshine days in May: 13.3 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 May
Charleston, SC

Average UV index in May - Charleston, SC
  • Average UV index in May: 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 May
Charleston, SC

Average cloud cover in May - Charleston, SC
  • Average cloud cover in May: 27

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 May
Charleston, SC

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