December weather forecast and climate
Manassas, VA

Weather in December

December, the first month of the winter, in Manassas, is still a chilly month, with average temperature varying between 32.4°F (0.2°C) and 45.7°F (7.6°C).

Temperature

In December, the average high-temperature slightly decreases, from a cool 54.5°F (12.5°C) in November, to a frosty 45.7°F (7.6°C). In December, in Manassas, the average low-temperature is 32.4°F (0.2°C).

Humidity

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

Rainfall

In December, the rain falls for 10.3 days. Throughout December, 2.56" (65mm) of precipitation is accumulated. Throughout the year, in Manassas, there are 157.5 rainfall days, and 30.35" (771mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, November and December. In Manassas, during December, snow falls for 2.5 days and regularly aggregates up to 1.61" (41mm) of snow. In Manassas, during the entire year, snow falls for 15.8 days, and aggregates up to 11.5" (292mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9.5h of daylight.

Sunshine

Months with the least sunshine in Manassas are January, February and December, with an average of 5.2h of sunshine.

UV index

Months with the lowest UV index in Manassas 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 unsafe exposure to the UV radiation for average individuals.
Note: In December, the average maximum UV index of 2 translate into the following recommendations:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. 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 most humid month in Manassas?

The most humid month in Manassas, Virginia, is December, with an average relative humidity of 78%.

What is the average humidity in December in Manassas?

The average relative humidity in December is 78%.

How much does it rain in Manassas in December?

In Manassas, Virginia, during December, the rain falls for 10.3 days and regularly aggregates up to 2.56" (65mm) of precipitation.

How much does it snow in Manassas in December?

In Manassas, Virginia, during December, snow falls for 2.5 days and regularly aggregates up to 1.61" (41mm) of snow.

What is the month with the shortest days in Manassas?

With an average of 9.5h of daylight, December has the shortest days of the year.

What is the average length of the day in December in Manassas?

In December, the average length of the day in Manassas, Virginia, is 9.5h.

What is the month with the least sunshine in Manassas?

Months with the least sunshine in Manassas, Virginia, are January, February and December, with an average of 5.2h of sunshine.

How long on average sun shines in December in Manassas?

In December, the average sunshine in Manassas is 5.2h.

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

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

What is the UV index reading in December in Manassas?

In Manassas, Virginia, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to the Sun's UV rays.

Average temperature in December
Manassas, VA

Average temperature in December - Manassas, VA
  • Average high temperature in December: 45.7°F

The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is January (40.6°F).

  • Average low temperature in December: 32.4°F

The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (26.4°F).

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Average pressure in December
Manassas, VA

Average pressure in December - Manassas, VA
  • Average pressure in December: 30.11"

The month with the highest atmospheric pressure is November (30.14").
The month with the lowest atmospheric pressure is June (29.95").

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Average wind speed in December
Manassas, VA

Average wind speed in December - Manassas, VA
  • Average wind speed in December: 6mph

The windiest months (with the highest average wind speed) are March and April (7mph).
The calmest month (with the lowest average wind speed) is August (4.6mph).

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Average humidity in December
Manassas, VA

Average humidity in December - Manassas, 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 (72%).

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Average rainfall in December
Manassas, VA

Average rainfall in December - Manassas, VA
  • Average rainfall in December: 2.56"

The wettest month (with the highest rainfall) is August (3.43").
The driest month (with the least rainfall) is September (1.93").

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Average rainfall days in December
Manassas, VA

Average rainfall days in December - Manassas, VA
  • Average rainfall days in December: 10.3 days

The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is November (9.3 days).

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Average snowfall in December
Manassas, VA

Average snowfall in December - Manassas, VA
  • Average snowfall in December: 1.61"

The month with the highest snowfall is January (3.7").
Months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in December
Manassas, VA

Average snowfall days in December - Manassas, VA
  • Average snowfall days in December: 2.5 days

The month with the highest number of snowfall days is February (5.2 days).
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
Manassas, VA

Average daylight in December / Average sunshine in December - Manassas, VA
  • Average daylight in December: 9.5h

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in December: 5.2h

The month with the most sunshine is July (Average sunshine: 10.7h).
Months with the least sunshine are January, February and December (Average sunshine: 5.2).

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Average sunshine days in December
Manassas, VA

Average sunshine days in December - Manassas, VA
  • Average sunshine days in December: 17.3 days

The month with the most sunshine days is November (19.8 days).
The month with the least sunshine days is May (11.7 days).

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Average UV index in December
Manassas, VA

Average UV index in December - Manassas, VA
  • Average UV index in December: 2

Months with the highest UV index are May, June, July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in December
Manassas, VA

Average cloud cover in December - Manassas, VA
  • Average cloud cover in December: 45

The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).

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Average visibility in December
Manassas, VA

Average visibility in December - Manassas, VA
  • Average visibility in December: 5mi

Months with the highest visibility are January, February, March, April, June, July, August and November (6mi).
Months with the lowest visibility are May, September, October and December (5mi).

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