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 results in a decrease in the average high-temperature, receding from a fresh 54.5°F (12.5°C) in November to a frosty 45.5°F (7.5°C). In Fairfax, an average low-temperature of 32.9°F (0.5°C) is recorded during December nights.Humidity
October and December, with an average relative humidity of 77%, are the most humid months.Rainfall
In December, the rain falls for 10.9 days. Throughout December, 2.72" (69mm) of precipitation is accumulated. In Fairfax, during the entire year, the rain falls for 162 days and collects up to 31.65" (804mm) of precipitation.Snowfall
Months with snowfall are January through April, November and December. In Fairfax, in December, during 3.1 snowfall days, 1.73" (44mm) of snow is typically accumulated. In Fairfax, Virginia, during the entire year, snow falls for 18 days and aggregates up to 11.18" (284mm) of snow.Daylight
With an average of 9h and 30min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:09 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:57 pm EST.
Sunshine
January, February and December, with an average of 5.2h of sunshine, are months with the least sunshine.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for the average person.Note: The maximum UV index of 2 during December translates into these guidelines:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key. Be on the lookout! Nearly twofold UV radiation from the Sun can be reflected by snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Fairfax in December?
What is the most humid month?
What is the average humidity in December?
How many days does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Fairfax have in December?
What time are sunrise and sunset in December?
What are the months with the least sunshine?
How long on average sun shines in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Fairfax, VA
- Average high temperature in December: 45.5°F
The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (40.5°F).
- Average low temperature in December: 32.9°F
The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (26.4°F).
Average pressure in December
Fairfax, VA
- 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
Fairfax, VA
- Average wind speed in December: 6.5mph
The windiest month (with the highest average wind speed) is March (7.4mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in December
Fairfax, VA
- Average humidity in December: 77%
The months with the highest relative humidity are October and December (77%).
The month with the lowest relative humidity is July (71%).
Average rainfall in December
Fairfax, VA
- Average rainfall in December: 2.72"
The wettest month (with the highest rainfall) is August (3.78").
The driest month (with the least rainfall) is September (2.01").
Average rainfall days in December
Fairfax, VA
- Average rainfall days in December: 10.9 days
The months with the highest number of rainy days are May and August (17.3 days).
The month with the least rainy days is November (9.1 days).
Average snowfall in December
Fairfax, VA
- Average snowfall in December: 1.73"
The month with the highest snowfall is January (3.54").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Fairfax, VA
- Average snowfall days in December: 3.1 days
The month with the highest number of snowfall days is January (5.6 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Fairfax, VA
- Average daylight in December: 9h and 3min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 5h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 12min).
Average sunshine days in December
Fairfax, VA
- Average sunshine days in December: 16.9 days
The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is July (11.3 days).
Average UV index in December
Fairfax, VA
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Fairfax, VA
- Average cloud cover in December: 44
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in December
Fairfax, VA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Fairfax, Virginia, USA
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