December 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 December

In December, Charleston residents brace for the winter chill. The change to colder weather is noticeable as daylight hours dwindle and twilight arrives earlier each day. A significant weather event in December is the increased precipitations at 4.25", cutting through the generally dry spell of preceding months. Despite a few gloomy days, Charleston still manages to retain some of its southern warmth during the last month of the year.

Temperature

The start of December sees the average high-temperature at a still refreshing 60.8°F, showing little difference from November's 65.7°F. Throughout the month of December, Charleston sees a steady low-temperature average of 49.3°F.

Humidity

With an average relative humidity of 78%, December is the most humid month.

Rainfall

In Charleston, during December, the rain falls for 11.1 days and regularly aggregates up to 4.25" of precipitation. In Charleston, during the entire year, the rain falls for 178.9 days and collects up to 41.93" of precipitation.

Snowfall

January and December are months with snowfall in Charleston. December is the first month it typically snows. Throughout December, in the average 0.1 snowfall days, it receives 0.04" of snow. Throughout the year, there are 0.6 snowfall days, and 0.16" of snow is accumulated.

Ocean temperature

In Charleston, in December, the average water temperature is 66.2°F.
Note: Most people do not take pleasure in swimming in water at 66.2°F. The difficulty of managing breathing increases as the water temperature dips from 69.8°F to 59°F.

Daylight

December has the shortest days of the year, with an average of 10h and 0min of daylight.
On the first day of the month, sunrise is at 7:04 am and sunset at 5:13 pm. On the last day of December, in Charleston, sunrise is at 7:21 am and sunset at 5:23 pm EST.

Sunshine

December has the least sunshine of the year, with an average of 5.7h of sunshine.

UV index

In December, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for the average person.
Note: The average daily UV index of 4 in December transforms into the following instructions:
Take necessary precautions - Suggestions to elude sunburn are provided. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Be vigilant! The reflective nature of snow can increase the Sun's UV radiation nearly twofold.
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FAQ

What are December temperatures in Charleston?

During December, Charleston experiences an average high-temperature of 60.8°F and a low-temperature of 49.3°F. In September, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, is evaluated at 91.4°F.

What is the most humid month in Charleston?

The most humid month in Charleston, South Carolina, is December, with an average relative humidity of 78%.

What is the average humidity in December in Charleston?

In Charleston, South Carolina, the average relative humidity in December is 78%.

How much does it rain in Charleston in December?

In Charleston, South Carolina, in December, during 11.1 rainfall days, 4.25" of precipitation is typically accumulated.

When does it start to snow in Charleston?

December is the first month it typically snows in Charleston, South Carolina. Throughout December, in the average 0.1 snowfall days, it receives 0.04" of snow.

What is the ocean temperature in December in Charleston?

In Charleston, in December, the average water temperature is 66.2°F. Swimming in 66.2°F is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F.

What is the month with the shortest days in Charleston?

The month with the shortest days in Charleston, South Carolina, is December, with an average of 10h and 0min of daylight.

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

The average day length in December is 10h and 2min.

What time are sunrise and sunset in December in Charleston?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 5:13 pm. On the last day of the month, in Charleston, South Carolina, sunrise is at 7:21 am and sunset at 5:23 pm EST.

What is the month with the least sunshine in Charleston?

December has the least sunshine of the year in Charleston, with an average of 5.7h of sunshine.

How long on average sun shines in December in Charleston?

The average sunshine duration in December is 5.7h.

What is the UV index intensity in December in Charleston?

In December, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate health threat from unsafe exposure to Sun's UV rays.
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 December
Charleston, SC

Average temperature in December - Charleston, SC
  • Average high temperature in December: 60.8°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 December: 49.3°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 December
Charleston, SC

Average pressure in December - Charleston, SC
  • Average pressure in December: 30.13"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 December
Charleston, SC

Average wind speed in December - Charleston, SC
  • Average wind speed in December: 8.7mph

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 December
Charleston, SC

Average humidity in December - Charleston, SC
  • Average humidity in December: 78%

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 December
Charleston, SC

Average rainfall in December - Charleston, SC
  • Average rainfall in December: 4.25"

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 December
Charleston, SC

Average rainfall days in December - Charleston, SC
  • Average rainfall days in December: 11.1 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 December
Charleston, SC

Average snowfall in December - Charleston, SC
  • Average snowfall in December: 0.04"

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 December
Charleston, SC

Average snowfall days in December - Charleston, SC
  • Average snowfall days in December: 0.1 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 December
Charleston, SC

Average sea temperature in December - Charleston, SC
  • Average sea temperature in December: 66.3°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 December /
Average sunshine in December
Charleston, SC

Average daylight in December / Average sunshine in December - Charleston, SC
  • Average daylight in December: 10h and 0min

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 December: 5h and 4min

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 December
Charleston, SC

Average sunshine days in December - Charleston, SC
  • Average sunshine days in December: 17.8 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 December
Charleston, SC

Average UV index in December - Charleston, SC
  • Average UV index in December: 4

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 December
Charleston, SC

Average cloud cover in December - Charleston, SC
  • Average cloud cover in December: 39

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 December
Charleston, SC

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