December weather forecastAshburn, VA
December
Weather in December
December in Ashburn heralds the winter season, and with it comes a marked shift in weather when compared to November and followed by January. The contrast lies most notably in its temperatures, with the lowest recorded at 32°F (0°C), serving as a precursor to January's colder days. During this holiday season, a level of cloud cover higher than in any other month signifies a typical winter outlook. The winter solstice brings the shortest daylight duration, collectively stacking all the signs of an imminent chill.Temperature
Ashburn's weather subtly changes with the onset of December, barely falling from a cool 53.6°F (12°C) in November to a chilly 45.1°F (7.3°C). Ashburn's average low-temperature for the month of December records at an icy 32°F (0°C).Humidity
With an average relative humidity of 78%, December is the most humid month.Rainfall
In Ashburn, in December, during 10.5 rainfall days, 2.68" (68mm) of precipitation is typically accumulated. Throughout the year, there are 158.1 rainfall days, and 31.46" (799mm) of precipitation is accumulated.Snowfall
Months with snowfall in Ashburn are January through April, November and December. In Ashburn, during December, snow falls for 2.7 days and regularly aggregates up to 1.97" (50mm) of snow. Throughout the year, there are 16.7 snowfall days, and 12.28" (312mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 30min of daylight.On the first day of the month, sunrise is at 7:10 am and sunset at 4:47 pm. On the last day of December, sunrise is at 7:28 am and sunset at 4:57 pm EST.
Sunshine
January, February and December, with an average of 5h 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 minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In December, the maximum UV index of 2 suggests this advice:
While many people can endure lengthy sun exposure, it remains imperative to safeguard babies, children, and fair-skinned individuals. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Notice this! Nearly double the intensity of the Sun's UV radiation can be caused by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Ashburn, VA
- Average high temperature in December: 45.1°F
The warmest month (with the highest average high temperature) is July (87.8°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in December: 32°F
The month with the highest average low temperature is July (67.3°F).
The coldest month (with the lowest average low temperature) is January (25.9°F).
Average pressure in December
Ashburn, 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
Ashburn, VA
- Average wind speed in December: 6.6mph
The windiest month (with the highest average wind speed) is March (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in December
Ashburn, VA
- Average humidity in December: 78%
The month with the highest relative humidity is December (78%).
The month with the lowest relative humidity is July (70%).
Average rainfall in December
Ashburn, VA
- Average rainfall in December: 2.68"
The wettest month (with the highest rainfall) is August (3.78").
The driest month (with the least rainfall) is September (1.93").
Average rainfall days in December
Ashburn, VA
- Average rainfall days in December: 10.5 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (9.3 days).
Average snowfall in December
Ashburn, VA
- Average snowfall in December: 1.97"
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
Ashburn, VA
- Average snowfall days in December: 2.7 days
The months with the highest number of snowfall days are January and February (5.1 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
Ashburn, VA
- Average daylight in December: 9h and 30min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 5h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 0min).
Average sunshine days in December
Ashburn, VA
- Average sunshine days in December: 17.5 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is July (11.8 days).
Average UV index in December
Ashburn, 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
Ashburn, VA
- Average cloud cover in December: 47
The month with the most cloud cover is March (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in December
Ashburn, 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).
