December weather forecast and climate
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 temperature in the range of an average low of 34.2°F (1.2°C) and an average high of 46°F (7.8°C).

Temperature

In Washington, the average high-temperature marginally drops, from a fresh 54.9°F (12.7°C) in November, to a chilly 46°F (7.8°C). The average low-temperature, in Washington, is 34.2°F (1.2°C).

Humidity

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

Rainfall

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

Snowfall

January through March and December are months with snowfall in Washington. 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

The month with the shortest days in Washington is December, with an average of 9.5h of daylight.

Sunshine

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

UV index

January and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a low health risk from unprotected exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 2 transform into the following instructions:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the average humidity in December in Washington?

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

How many days does it rain in December in Washington?

In December, the rain falls for 10 days. Throughout December, 1.93" (49mm) of precipitation is 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?

With an average of 9.5h of daylight, December has the shortest days of the year.

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

In December, the average length of the day in Washington, District of Columbia, is 9.5h.

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.

How long on average sun shines in December in Washington?

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

When is the lowest UV index in Washington?

Months with the lowest UV index are January and December, with an average maximum UV index of 2.

What is the UV index intensity in December in Washington?

The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from the exposure to the Sun's UV radiation.

Average temperature in December
Washington, DC

Average temperature in December - Washington, DC
  • Average high temperature in December: 7.8°C

The warmest month (with the highest average high temperature) is July (31.1°C).
The month with the lowest average high temperature is January (4.8°C).

  • Average low temperature in December: 1.2°C

The month with the highest average low temperature is July (20.6°C).
The coldest month (with the lowest average low temperature) is January (-2.5°C).

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Average pressure in December
Washington, DC

Average pressure in December - Washington, DC
  • Average pressure in December: 1019.7mbar

The month with the highest atmospheric pressure is November (1020.6mbar).
The month with the lowest atmospheric pressure is June (1014.1mbar).

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Average wind speed in December
Washington, DC

Average wind speed in December - Washington, DC
  • Average wind speed in December: 11.3km/h

The windiest month (with the highest average wind speed) is March (12.7km/h).
The calmest month (with the lowest average wind speed) is August (8.1km/h).

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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%).
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: 49mm

The wettest month (with the highest rainfall) is August (88mm).
The driest month (with the least rainfall) is January (40mm).

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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: 20mm

The month with the highest snowfall is January (55mm).
Months with the least snowfall are April, May, June, July, August, September, October and November (0mm).

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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

Months with the highest number of snowfall days are January and February (3.8 days).
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: 9.5h

The month with the longest days is June (Average daylight: 14.9h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in December: 5.1h

The month with the most sunshine is July (Average sunshine: 10.7h).
Months with the least sunshine are January, February and December (Average sunshine: 5.1).

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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).
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: 9km

Months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (9km).
The month with the lowest visibility is May (8km).

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