December weather forecast
Washington, DC

Rows of jacaranda trees in spring in the tidal basin of the Washington Monument in Washington city, DC, USA
Rows of jacaranda trees in spring in the tidal basin of the Washington Monument in Washington city, DC, USA

Weather in December

The first month of the winter, December, is also a frosty month in Washington, District of Columbia, with an average temperature fluctuating between 34.2°F (1.2°C) and 46°F (7.8°C).

Temperature

In Washington, the average high-temperature in December slightly decreases from a fresh 54.9°F (12.7°C) in November to a frosty 46°F (7.8°C). In Washington, District of Columbia, the average low-temperature is 34.2°F (1.2°C).

Humidity

In December, the average relative humidity is 75%.

Rainfall

In December, in Washington, the rain falls for 10 days. Throughout December, 1.93" (49mm) of precipitation is accumulated. Throughout the year, there are 149.1 rainfall days, and 26.14" (664mm) of precipitation is accumulated.

Snowfall

January through March and December are months with snowfall. December is the first month it typically snows. Throughout December, in the average 1.7 snowfall days, it receives 0.79" (20mm) of snow. In Washington, during the entire year, snow falls for 11.7 days and aggregates up to 6.3" (160mm) of snow.

Daylight

With an average of 9h and 29min of daylight, December has the shortest days of the year in Washington.
On the first day of December, sunrise is at 7:07 am and sunset at 4:46 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:55 pm EST.

Sunshine

The months with the least sunshine are January, February and December, with an average of 5.1h of sunshine.

UV index

The months with the lowest UV index in Washington, District of Columbia, are January and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The daily maximum UV index of 2 in December interpret into the following advice:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. 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 increased nearly double-fold by the reflection of the snow.
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FAQ

What is the average humidity in December in Washington?

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

How many days does it rain in December in Washington?

In Washington, in December, during 10 rainfall days, 1.93" (49mm) of precipitation is typically accumulated.

When does it start snowing in Washington?

December is the first month it typically snows in Washington, District of Columbia. Throughout December, in the average 1.7 snowfall days, it receives 0.79" (20mm) of snow.

What is the month with the shortest days in Washington?

December has the shortest days of the year in Washington, District of Columbia, with an average of 9h and 29min of daylight.

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

In December, the average day length in Washington, District of Columbia, is 9h and 29min.

When is the sunrise / sunset in December in Washington?

In December, on the first day of the month, sunrise is at 7:07 am and sunset at 4:46 pm. On the last day of the month, in Washington, District of Columbia, sunrise is at 7:26 am and sunset at 4:55 pm EST.

What is the month with the least sunshine in Washington?

January, February and December, with an average of 5.1h of sunshine, are months with the least sunshine in Washington.

How many hours of sunshine does Washington have in December?

In December, the average sunshine duration in Washington, District of Columbia, is 5.1h.

What are the months with the lowest UV index in Washington?

The months with the lowest UV index in Washington are January and December, with an average maximum UV index of 2.

What is the UV index reading in December in Washington?

In Washington, the average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Washington, DC

Average temperature in December - Washington, DC
  • Average high temperature in December: 46°F

The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (40.6°F).

  • Average low temperature in December: 34.2°F

The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is January (27.5°F).

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Average pressure in December
Washington, DC

Average pressure in December - Washington, DC
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

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Average wind speed in December
Washington, DC

Average wind speed in December - Washington, DC
  • Average wind speed in December: 7mph

The windiest month (with the highest average wind speed) is March (7.9mph).
The calmest month (with the lowest average wind speed) is August (5mph).

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Average humidity in December
Washington, DC

Average humidity in December - Washington, DC
  • Average humidity in December: 75%

The month with the highest relative humidity is May (76%).
The months with the lowest relative humidity are April and July (71%).

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Average rainfall in December
Washington, DC

Average rainfall in December - Washington, DC
  • Average rainfall in December: 1.93"

The wettest month (with the highest rainfall) is August (3.46").
The driest month (with the least rainfall) is January (1.57").

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Average rainfall days in December
Washington, DC

Average rainfall days in December - Washington, DC
  • Average rainfall days in December: 10 days

The month with the highest number of rainy days is July (16.4 days).
The month with the least rainy days is November (8.1 days).

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Average snowfall in December
Washington, DC

Average snowfall in December - Washington, DC
  • Average snowfall in December: 0.79"

The month with the highest snowfall is January (2.17").
The months with the least snowfall are April, May, June, July, August, September, October and November (0").

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Average snowfall days in December
Washington, DC

Average snowfall days in December - Washington, DC
  • Average snowfall days in December: 1.7 days

The months with the highest number of snowfall days are January and February (3.8 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
Washington, DC

Average daylight in December / Average sunshine in December - Washington, DC
  • Average daylight in December: 9h and 29min

The month with the longest days is June (Average daylight: 14h and 51min).
The month with the shortest days is December (Average daylight: 9h and 29min).

  • Average sunshine in December: 5h and 6min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 6min).

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Average sunshine days in December
Washington, DC

Average sunshine days in December - Washington, DC
  • Average sunshine days in December: 19 days

The month with the most sunshine days is November (20 days).
The month with the least sunshine days is May (12.8 days).

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Average UV index in December
Washington, DC

Average UV index in December - Washington, DC
  • Average UV index in December: 2

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

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Average cloud cover in December
Washington, DC

Average cloud cover in December - Washington, DC
  • Average cloud cover in December: 45

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).

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Average visibility in December
Washington, DC

Average visibility in December - Washington, DC
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).

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