Washington
District of Columbia, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Washington, DC

Stunning reflective view of rows of jacaranda trees in spring in the tidal basin of the Washington Monument in DC
Stunning reflective view of rows of jacaranda trees in spring in the tidal basin of the Washington Monument in DC
The first month of the winter, December, is also a frosty month in Washington, District of Columbia, with average temperature varying 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 cool 54.9°F (12.7°C) in November, to a frosty 46°F (7.8°C). In Washington, in December, the average low-temperature is 34.2°F (1.2°C).

Humidity

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

Rainfall

In Washington, during 10 rainfall days, 1.93" (49mm) of precipitation is typically accumulated. In Washington, during the entire year, the rain falls for 149.1 days and collects up to 26.14" (664mm) of precipitation.

Snowfall

Months with snowfall in Washington are January through March and December. 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 is December, with an average of 9.5h of daylight.

Sunshine

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

UV index

January and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to the UV radiation 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. 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. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the temperature in December in Washington?

In Washington, District of Columbia, in December, the average high-temperature is 46°F (7.8°C), and the average low-temperature is 34.2°F (1.2°C).

What is the average humidity in December in Washington?

In Washington, the average relative humidity in December 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 to snow 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.

What is the month with the shortest days in Washington?

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

How many hours of daylight does Washington have in December?

The average length of the day in December in Washington 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 in Washington, District of Columbia.

How long on average sun shines in December in Washington?

The average sunshine in December is 5.1h.

What is the month with the lowest UV index in Washington?

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

How high is the UV index 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 low health threat from unsafe exposure to the Sun's UV rays.
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).

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%).

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 lowest rainfall) is January (40mm).

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 lowest number of rainy days is November (8.1 days).

Average snowfall in December - Washington, DC
  • Average snowfall in December: 20mm

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

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 lowest number of snowfall days are April, May, June, July, August, September and October (0 days).

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 shortest days is December (Average daylight: 9.5h).

  • Average sunshine in December: 5.1h

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

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).