December weather forecast
Irmo, SC

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Weather in December

In December, Irmo, South Carolina, experiences the chill of winter with temperatures hitting their lowest for the year. It's a time of year marked by cozy indoor activities, warm drinks, and the holiday season. A slight snowfall of 0.08" (2mm) can be witnessed, indicating the arrival of winter. The increase in cloud cover, along with shorter daylight hours, further accentuates the wintry atmosphere. Bidding goodbye to the year, residents prepare for January, continuing the cycle of weather changes with its distinct cold.

Temperature

The onset of December in Irmo, South Carolina, results in a small decrease in the average high-temperature, moderately receding from an enjoyable 62.2°F (16.8°C) in November to a mild 55.8°F (13.2°C). Throughout December, an average nighttime temperature of 41.2°F (5.1°C) is experienced in Irmo, South Carolina.

Humidity

The most humid month is December, with an average relative humidity of 75%.

Rainfall

The month with the most rainfall is December, when the rain falls for 11.1 days and typically aggregates up to 3.11" (79mm) of precipitation.

Snowfall

Months with snowfall in Irmo are January through March and December. December is the first month it typically snows. Throughout December, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow. Throughout the year, there are 1.2 snowfall days, and 0.79" (20mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 54min of daylight.
On the first day of December, sunrise is at 7:12 am and sunset at 5:15 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 5:25 pm EST.

Sunshine

December has the least sunshine of the year, with an average of 5.5h of sunshine.

UV index

In Irmo, South Carolina, the average daily maximum UV index in December is 3. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: The UV index of 3 in December translates into these instructions:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Attention! Nearly twice the Sun's UV radiation can be reflected by snow.
Updated: Aug 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in December?

An average high-temperature, in December, in Irmo, is 55.8°F (13.2°C) and the average low-temperature is 41.2°F (5.1°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which factors the actual air temperature with the relative humidity, in September is evaluated at 93.2°F (34°C).

What is the most humid month?

With an average relative humidity of 75%, December is the most humid month.

What is the average humidity in December?

In December, the average relative humidity in Irmo is 75%.

What is the rainiest month in Irmo?

The month with the most rainfall in Irmo is December, when the rain falls for 11.1 days and typically aggregates up to 3.11" (79mm) of precipitation.

How many days does it rain in December in Irmo?

In Irmo, in December, during 11.1 rainfall days, 3.11" (79mm) of precipitation is typically accumulated.

When does it start snowing?

December is the first month it typically snows. Throughout December, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow.

What is the month with the shortest days?

With an average of 9h and 54min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

In December, the average day length is 9h and 56min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:12 am and sunset at 5:15 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 5:25 pm EST.

What is the month with the least sunshine?

With an average of 5.5h of sunshine, December has the least sunshine of the year.

How long on average sun shines in December in Irmo?

In December, the average sunshine duration is 5.5h.

What is the UV index intensity in December?

In Irmo, the average daily maximum UV index in December is 3. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from exposure to the Sun's UV radiation.
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 December
Irmo, SC

Average temperature in December - Irmo, SC
  • Average high temperature in December: 55.8°F

The warmest month (with the highest average high temperature) is July (91.4°F).
The month with the lowest average high temperature is January (52.3°F).

  • Average low temperature in December: 41.2°F

The month with the highest average low temperature is July (72.9°F).
The coldest month (with the lowest average low temperature) is January (36.9°F).

Average pressure in December
Irmo, SC

Average pressure in December - Irmo, SC
  • Average pressure in December: 30.14"Hg

The months with the highest atmospheric pressure are January, November and December (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.97"Hg).

Average wind speed in December
Irmo, SC

Average wind speed in December - Irmo, SC
  • Average wind speed in December: 7.3mph

The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

Average humidity in December
Irmo, SC

Average humidity in December - Irmo, SC
  • Average humidity in December: 75%

The month with the highest relative humidity is December (75%).
The month with the lowest relative humidity is July (70%).

Average rainfall in December
Irmo, SC

Average rainfall in December - Irmo, SC
  • Average rainfall in December: 3.11"

The wettest month (with the highest rainfall) is December (3.11").
The driest month (with the least rainfall) is September (1.54").

Average rainfall days in December
Irmo, SC

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

The month with the highest number of rainy days is July (17.4 days).
The month with the least rainy days is October (7.8 days).

Average snowfall in December
Irmo, SC

Average snowfall in December - Irmo, SC
  • Average snowfall in December: 0.08"

The month with the highest snowfall is February (0.43").
The months with the least snowfall are April, May, June, July, August, September, October and November (0").

Average snowfall days in December
Irmo, SC

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

The month with the highest number of snowfall days is January (0.5 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).

Average daylight in December /
Average sunshine in December
Irmo, SC

Average daylight in December / Average sunshine in December - Irmo, SC
  • Average daylight in December: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in December: 5h and 3min

The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).

Average sunshine days in December
Irmo, SC

Average sunshine days in December - Irmo, SC
  • Average sunshine days in December: 18.8 days

The month with the most sunshine days is October (21.8 days).
The month with the least sunshine days is July (10.8 days).

Average UV index in December
Irmo, SC

Average UV index in December - Irmo, SC
  • Average UV index in December: 3

The months with the highest UV index are June and July (UV index 7).
The month with the lowest UV index is January (UV index 2).

Average cloud cover in December
Irmo, SC

Average cloud cover in December - Irmo, SC
  • Average cloud cover in December: 41

The months with the most cloud cover are February and December (Cloud cover 41).
The months with the least cloud cover are June and October (Cloud cover 28).

Average visibility in December
Irmo, SC

Average visibility in December - Irmo, 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).

Irmo, South Carolina, USA

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