December weather forecast
Ashburn, VA

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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

December's onset in Ashburn brings a negligible change in high-temperatures, falling from a fresh 53.6°F (12°C) in November to a frosty 45.1°F (7.3°C). In December, Ashburn's temperature tends to fall to an average low of 32°F (0°C) during the night.

Humidity

With an average relative humidity of 78%, December is the most humid month in Ashburn.

Rainfall

In Ashburn, in December, it is raining for 10.5 days, with typically 2.68" (68mm) of accumulated precipitation. Throughout the year, there are 158.1 rainfall days, and 31.46" (799mm) of precipitation is accumulated.

Snowfall

January through April, November and December are months with snowfall. In December, it is snowing for 2.7 days. Throughout December, 1.97" (50mm) of snow is accumulated. In Ashburn, during the entire year, snow falls for 16.7 days and aggregates up to 12.28" (312mm) of snow.

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 in Ashburn.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Ashburn. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for average individuals.
Note: The UV index of 2 during December translates into the following guidance:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.
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Frequently asked questions

What is the average December temperature in Ashburn?

An average high-temperature, in December, in Ashburn, is 45.1°F (7.3°C) and the average low-temperature is 32°F (0°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in August is computed to be 95°F (35°C).

What is the most humid month in Ashburn?

December is the most humid month, with an average relative humidity of 78%.

What is the average humidity in December in Ashburn?

The average relative humidity in December in Ashburn is 78%.

How much does it rain in Ashburn in December?

In Ashburn, during December, the rain falls for 10.5 days and regularly aggregates up to 2.68" (68mm) of precipitation.

How much does it snow in Ashburn in December?

In Ashburn, in December, snow falls for 2.7 days, with typically accumulated 1.97" (50mm) of snow.

What is the month with the shortest days in Ashburn?

The month with the shortest days is December, with an average of 9h and 30min of daylight.

How many hours of daylight does Ashburn have in December?

In December, the average day length in Ashburn, Virginia, is 9h and 29min.

When are sunrise and sunset in December in Ashburn?

In December, on the first day of the month, sunrise is at 7:10 am and sunset at 4:47 pm. On the last day of the month, in Ashburn, Virginia, sunrise is at 7:28 am and sunset at 4:57 pm EST.

What are the months with the least sunshine in Ashburn?

The months with the least sunshine in Ashburn, Virginia, are January, February and December, with an average of 5h of sunshine.

How long on average sun shines in December in Ashburn?

The average sunshine duration in December is 5h.

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

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Ashburn, Virginia.

How high is the UV index in December in Ashburn?

The average daily maximum UV index in December is 2. A UV Index 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
Ashburn, VA

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).

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Average pressure in December
Ashburn, VA

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).

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Average wind speed in December
Ashburn, VA

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).

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Average humidity in December
Ashburn, VA

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%).

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Average rainfall in December
Ashburn, VA

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").

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Average rainfall days in December
Ashburn, VA

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).

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Average snowfall in December
Ashburn, VA

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").

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Average snowfall days in December
Ashburn, VA

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).

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Average daylight in December /
Average sunshine in December
Ashburn, VA

Average daylight in December / Average sunshine in December - Ashburn, VA
  • Average daylight in December: 9h and 3min

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).

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Average sunshine days in December
Ashburn, VA

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).

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Average UV index in December
Ashburn, VA

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).

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Average cloud cover in December
Ashburn, VA

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).

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Average visibility in December
Ashburn, VA

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).

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Ashburn, Virginia, USA

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