December weather forecast
Washington, NJ

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Weather in December

December, the first month of the winter in Washington, is also a wintry month, with an average temperature fluctuating between 40.1°F (4.5°C) and 28.4°F (-2°C).

Temperature

The arrival of December signals a shift in temperature, down from a chilly 49.8°F (9.9°C) in November to a cold 40.1°F (4.5°C). Washington's average low-temperature in the month of December is recorded at a subzero cold 28.4°F (-2°C).

Humidity

The average relative humidity in December is 80%.

Rainfall

In December, the rain falls for 11.7 days. Throughout December, 2.8" (71mm) of precipitation is accumulated. In Washington, during the entire year, the rain falls for 157.6 days and collects up to 28.7" (729mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Washington, during December, snow falls for 4.9 days and regularly aggregates up to 2.4" (61mm) of snow. Throughout the year, there are 30.4 snowfall days, and 14.76" (375mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 18min of daylight.
On the first day of the month, sunrise is at 7:05 am and sunset at 4:33 pm. On the last day of December, sunrise is at 7:23 am and sunset at 4:42 pm EST.

Sunshine

In Washington, the average sunshine in December is 4.7h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: In December, the maximum UV index of 2 transforms into these recommendations:
While most people can stay under the sun for an hour without burning, children must always be guarded against sun exposure. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
Updated: Jun 23, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is December cold?

In December, the average high-temperature and low-temperature are 40.1°F (4.5°C) and 28.4°F (-2°C) respectively. The average heat index (a.k.a. 'real feel', 'feels like'), which factors the actual air temperature with the relative humidity, in August is appraised at 86°F (30°C).

What is the average humidity in December?

In December, the average relative humidity is 80%.

How much does it rain in December?

In Washington, in December, it is raining for 11.7 days, with typically 2.8" (71mm) of accumulated precipitation.

How much does it snow in Washington in December?

In Washington, in December, during 4.9 snowfall days, 2.4" (61mm) of snow is typically accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 18min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 19min.

What time are sunrise and sunset in December in Washington?

On the first day of December, sunrise is at 7:05 am and sunset at 4:33 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:42 pm EST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.7h.

What is the month with the lowest UV index?

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

What is the UV index reading in December?

In December, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a minimal hazard to health 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, NJ

Average temperature in December - Washington, NJ
  • Average high temperature in December: 40.1°F

The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (34°F).

  • Average low temperature in December: 28.4°F

The month with the highest average low temperature is July (63°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).

Average pressure in December
Washington, NJ

Average pressure in December - Washington, NJ
  • Average pressure in December: 30.09"Hg

The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Washington, NJ

Average wind speed in December - Washington, NJ
  • Average wind speed in December: 7.3mph

The windiest month (with the highest average wind speed) is March (8.1mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).

Average humidity in December
Washington, NJ

Average humidity in December - Washington, NJ
  • Average humidity in December: 80%

The month with the highest relative humidity is February (81%).
The month with the lowest relative humidity is April (76%).

Average rainfall in December
Washington, NJ

Average rainfall in December - Washington, NJ
  • Average rainfall in December: 2.8"

The wettest month (with the highest rainfall) is July (2.87").
The driest month (with the least rainfall) is September (1.54").

Average rainfall days in December
Washington, NJ

Average rainfall days in December - Washington, NJ
  • Average rainfall days in December: 11.7 days

The month with the highest number of rainy days is May (16.5 days).
The month with the least rainy days is January (8.1 days).

Average snowfall in December
Washington, NJ

Average snowfall in December - Washington, NJ
  • Average snowfall in December: 2.4"

The month with the highest snowfall is February (3.82").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Washington, NJ

Average snowfall days in December - Washington, NJ
  • Average snowfall days in December: 4.9 days

The month with the highest number of snowfall days is January (8.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Washington, NJ
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 4h and 4min

The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in December
Washington, NJ

Average sunshine days in December - Washington, NJ
  • Average sunshine days in December: 16 days

The month with the most sunshine days is November (17.5 days).
The month with the least sunshine days is April (11.8 days).

Average UV index in December
Washington, NJ

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

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in December
Washington, NJ

Average cloud cover in December - Washington, NJ
  • Average cloud cover in December: 49

The month with the most cloud cover is February (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 34).

Average visibility in December
Washington, NJ

Average visibility in December - Washington, NJ
  • Average visibility in December: 5mi

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

Washington, New Jersey, USA

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