December weather forecast
Washington, PA

Weather in December

The first month of the winter, December, is also a wintry month in Washington, Pennsylvania, with an average temperature fluctuating between 40.1°F (4.5°C) and 28.6°F (-1.9°C).

Temperature

In Washington, the average high-temperature in December drops from a chilly 49.5°F (9.7°C) in November to a wintry 40.1°F (4.5°C). The average low-temperature, in Washington, is 28.6°F (-1.9°C).

Humidity

The average relative humidity in December in Washington is 84%.

Rainfall

In December, the rain falls for 9.4 days. Throughout December, 1.06" (27mm) of precipitation is accumulated. In Washington, during the entire year, the rain falls for 143 days and collects up to 14.8" (376mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. In Washington, during 6.5 snowfall days, 0.83" (21mm) of snow is typically accumulated. In Washington, during the entire year, snow falls for 33.5 days and aggregates up to 4.88" (124mm) of snow.

Daylight

With an average of 9h and 22min of daylight, December has the shortest days of the year in Washington.
On the first day of the month, sunrise is at 7:23 am and sunset at 4:55 pm. On the last day of December, in Washington, sunrise is at 7:43 am and sunset at 5:04 pm EST.

Sunshine

In Washington, the average sunshine in December is 3.5h.

UV index

With an average maximum UV index of 1, December is the month with the lowest UV index in Washington. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the average person.
Note: In December, the average maximum UV index of 1 translate into the following recommendations:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. 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 temperature in December in Washington?

In December, in Washington, the average high-temperature is 40.1°F (4.5°C), and the average low-temperature is 28.6°F (-1.9°C). in August, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines relative humidity and air temperature, is evaluated at 87.8°F (31°C).

What is the average humidity in December in Washington?

In December, the average relative humidity in Washington is 84%.

How much does it rain in Washington in December?

In Washington, in December, during 9.4 rainfall days, 1.06" (27mm) of precipitation is typically accumulated.

How much does it snow in Washington in December?

In Washington, in December, snow falls for 6.5 days, with typically accumulated 0.83" (21mm) of snow.

What is the month with the shortest days in Washington?

The month with the shortest days in Washington, Pennsylvania, is December, with an average of 9h and 22min of daylight.

How many hours of daylight does Washington have in December?

The average day length in December is 9h and 22min.

When are sunrise and sunset in December in Washington?

In December, on the first day of the month, sunrise is at 7:23 am and sunset at 4:55 pm. On the last day of the month, in Washington, sunrise is at 7:43 am and sunset at 5:04 pm EST.

How many hours of sunshine does Washington have in December?

The average sunshine duration in December in Washington is 3.5h.

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

December is the month with the lowest UV index, with an average maximum UV index of 1.

What is the UV index intensity in December in Washington?

In December, the average daily maximum UV index in Washington is 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to Sun's UV rays.
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, PA

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

The warmest month (with the highest average high temperature) is July (83.3°F).
The month with the lowest average high temperature is January (33.6°F).

  • Average low temperature in December: 28.6°F

The month with the highest average low temperature is July (61.9°F).
The coldest month (with the lowest average low temperature) is January (20.8°F).

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Average pressure in December
Washington, PA

Average pressure in December - Washington, PA
  • 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, PA

Average wind speed in December - Washington, PA
  • Average wind speed in December: 7.1mph

The windiest month (with the highest average wind speed) is January (7.8mph).
The calmest month (with the lowest average wind speed) is August (4.5mph).

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Average humidity in December
Washington, PA

Average humidity in December - Washington, PA
  • Average humidity in December: 84%

The month with the highest relative humidity is February (85%).
The months with the lowest relative humidity are April, July and August (77%).

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Average rainfall in December
Washington, PA

Average rainfall in December - Washington, PA
  • Average rainfall in December: 1.06"

The wettest month (with the highest rainfall) is July (1.65").
The driest months (with the least rainfall) are January and November (0.94").

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Average rainfall days in December
Washington, PA

Average rainfall days in December - Washington, PA
  • Average rainfall days in December: 9.4 days

The month with the highest number of rainy days is May (17.2 days).
The month with the least rainy days is February (7.3 days).

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Average snowfall in December
Washington, PA

Average snowfall in December - Washington, PA
  • Average snowfall in December: 0.83"

The month with the highest snowfall is February (1.26").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Washington, PA

Average snowfall days in December - Washington, PA
  • Average snowfall days in December: 6.5 days

The month with the highest number of snowfall days is January (9.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Washington, PA
  • Average daylight in December: 9h and 22min

The month with the longest days is June (Average daylight: 14h and 59min).
The month with the shortest days is December (Average daylight: 9h and 22min).

  • Average sunshine in December: 3h and 30min

The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).

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Average sunshine days in December
Washington, PA

Average sunshine days in December - Washington, PA
  • Average sunshine days in December: 17.5 days

The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is May (11.8 days).

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Average UV index in December
Washington, PA

Average UV index in December - Washington, PA
  • Average UV index in December: 1

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).

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Average cloud cover in December
Washington, PA

Average cloud cover in December - Washington, PA
  • Average cloud cover in December: 64

The month with the most cloud cover is January (Cloud cover 68).
The month with the least cloud cover is August (Cloud cover 33).

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Average visibility in December
Washington, PA

Average visibility in December - Washington, PA
  • 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).

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