May 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 May

May nudges Charleston into the noisy, chaotic season of summer. As temperatures inch higher, residents brace for longer, sunnier days. Amidst these warming trends, the interesting facet of May's weather is the significantly high rainfall of 2.87" that the city receives. The sea begins to warm up, becoming agreeable for water sports and other activities.

Temperature

May showcases a minor temperature ascent, adjusting from April's agreeable 72.7°F to a moderately hot 79.5°F. Charleston experiences a steady low-temperature of 68.2°F throughout May.

Humidity

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

Rainfall

In Charleston, South Carolina, in May, during 15.8 rainfall days, 2.87" of precipitation is typically accumulated. Throughout the year, in Charleston, there are 178.9 rainfall days, and 41.93" of precipitation is accumulated.

Snowfall

February through November are months without snowfall in Charleston.

Ocean temperature

In Charleston, South Carolina, in May, the average water temperature is 73°F.
Note: For someone sensitive to cold, swimming in 73°F waters can be invigorating, especially when considering elements like sunshine, wind, and current air temperature. (As a reference, Olympic swimming waters are kept between 77°F and 82.4°F.)

Daylight

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

The average sunshine in May in Charleston is 10.5h.

UV index

May through August, with an average maximum UV index of 7, are months with the highest UV index. A UV Index value of 6 to 7 symbolizes a high threat to health from unsafe exposure to UV radiation for the average person.
Note: In May, the maximum UV index of 7 suggests these recommendations:
Steer clear of overexposure. Fair-skinned individuals can be scorched in less than 20 minutes. Stay out of direct sunlight between 10 a.m. and 4 p.m., when UV radiation is most intense, and remember that not all shade structures provide complete protection. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Stay vigilant! UV rays get a boost in intensity due to sand and water reflections.
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FAQ

What is the usual temperature for Charleston in May?

In May, in Charleston, the average high-temperature is 79.5°F, and the average low-temperature is 68.2°F.

What is the average humidity in May in Charleston?

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

How many days does it rain in May in Charleston?

In Charleston, South Carolina, during May, the rain falls for 15.8 days and regularly aggregates up to 2.87" of precipitation.

When it does not snow in Charleston?

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

How warm is the water in May in Charleston?

In Charleston, in May, the average water temperature is 73°F. Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 73°F water may be enjoyable.

How many hours of daylight does Charleston have in May?

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

When is the sunrise / sunset in May in Charleston?

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.

How long on average sun shines in May in Charleston?

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

When is the highest UV index in Charleston?

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

What is the UV index intensity in May in Charleston?

The average daily maximum UV index in May in Charleston is 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to UV radiation.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average sea temperature
Average daylight
Average sunshine
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 5min

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 May: 10h and 3min

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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Charleston, South Carolina, USA

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