Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The onset of December brings a small change in high-temperatures, falling from a frosty 49.5°F (9.7°C) in November to a wintry 40.1°F (4.5°C). Washington experiences a consistent average temperature of 28.6°F (-1.9°C) throughout the nights in December.Humidity
The average relative humidity in December is 84%.Rainfall
In Washington, in December, it is raining for 9.4 days, with typically 1.06" (27mm) of accumulated precipitation. In Washington, during the entire year, the rain falls for 143 days and collects up to 14.8" (376mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In Washington, during December, snow falls for 6.5 days and regularly aggregates up to 0.83" (21mm) of snow. Throughout the year, there are 33.5 snowfall days, and 4.88" (124mm) of snow is accumulated.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:24 am and sunset at 4:55 pm. On the last day of the month, sunrise is at 7:43 am and sunset at 5:05 pm EST.
Sunshine
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. A UV Index value of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for the average person.Note: A maximum high daily UV index of 1 during December translates into the following directions:
Extended sunlight exposure does not pose significant problems for most people, except for children, infants, and people with fair skin who always need shielding. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold during December?
What is the average humidity in December?
How many days does it rain in December in Washington?
How much does it snow in Washington in December?
What is the month with the shortest days?
What is the average length of the day in December?
When is the sunrise / sunset in December?
How long on average sun shines in December?
What is the month with the lowest UV index?
What is the UV index intensity in December?
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).
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).
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).
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%).
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").
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).
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").
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).
Average daylight in December /
Average sunshine in December
Washington, PA
- 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 24min).
- Average sunshine in December: 3h and 3min
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).
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).
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).
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).
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).
Washington, Pennsylvania, USA
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