December weather forecast
Chantilly, VA

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Weather in December

The first month of the winter, December, is also a frosty month in Chantilly, Virginia, with temperature in the range of an average low of 32.2°F (0.1°C) and an average high of 45.3°F (7.4°C).

Temperature

The beginning of December brings a slight decrease in the average high-temperature, transitioning from a fresh 53.6°F (12°C) in November to a frosty 45.3°F (7.4°C). Chantilly records a mean low-temperature of 32.2°F (0.1°C) in December.

Humidity

October and December, with an average relative humidity of 77%, are the most humid months.

Rainfall

In Chantilly, in December, it is raining for 10.4 days, with typically 2.68" (68mm) of accumulated precipitation. In Chantilly, during the entire year, the rain falls for 156 days and collects up to 31.18" (792mm) of precipitation.

Snowfall

January through April, November and December are months with snowfall. In Chantilly, in December, snow falls for 2.7 days, with typically accumulated 1.97" (50mm) of snow. In Chantilly, during the entire year, snow falls for 16.8 days and aggregates up to 12.48" (317mm) 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 the month, sunrise is at 7:09 am and sunset at 4:48 pm. On the last day of December, sunrise is at 7:28 am and sunset at 4:57 pm EST.

Sunshine

The months with the least sunshine are January, February and December, with an average of 5.1h of 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 of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation for average individuals.
Note: The maximum daily UV index of 2 in December converts into the following recommendations:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
Updated: Jul 15, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in December in Chantilly?

December temperatures vary between a high-temperature of 45.3°F (7.4°C) and a low-temperature of 32.2°F (0.1°C). The average heat index (a.k.a. 'real feel', 'feels like'), which combines air temperature and relative humidity, in August is appraised at 95°F (35°C).

What is the most humid month?

October and December, with an average relative humidity of 77%, are most humid months.

What is the average humidity in December?

In Chantilly, the average relative humidity in December is 77%.

How many days does it rain in December?

In December, the rain falls for 10.4 days. Throughout December, 2.68" (68mm) of precipitation is accumulated.

How many days does it snow in December in Chantilly?

In Chantilly, in December, during 2.7 snowfall days, 1.97" (50mm) of snow is typically accumulated.

What is the month with the shortest days?

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

What is the average length of the day in December?

In Chantilly, the average day length in December is 9h and 30min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:09 am and sunset at 4:48 pm. On the last day of the month, sunrise is at 7:28 am and sunset at 4:57 pm EST.

What are the months with the least sunshine?

January, February and December, with an average of 5.1h of sunshine, are months with the least sunshine.

How long on average sun shines in December?

In Chantilly, the average sunshine duration in December is 5.1h.

What are the months with the lowest UV index?

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

What is the UV index intensity in December?

In December, the average daily maximum UV index in Chantilly is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability 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
Chantilly, VA

Average temperature in December - Chantilly, VA
  • Average high temperature in December: 45.3°F

The warmest month (with the highest average high temperature) is July (88.2°F).
The month with the lowest average high temperature is January (39.7°F).

  • Average low temperature in December: 32.2°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 (25.7°F).

Average pressure in December
Chantilly, VA

Average pressure in December - Chantilly, 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
Chantilly, VA

Average wind speed in December - Chantilly, VA
  • Average wind speed in December: 6.5mph

The windiest months (with the highest average wind speed) are March and April (7.3mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).

Average humidity in December
Chantilly, VA

Average humidity in December - Chantilly, 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
Chantilly, VA

Average rainfall in December - Chantilly, VA
  • Average rainfall in December: 2.68"

The wettest month (with the highest rainfall) is August (3.74").
The driest month (with the least rainfall) is September (1.89").

Average rainfall days in December
Chantilly, VA

Average rainfall days in December - Chantilly, VA
  • Average rainfall days in December: 10.4 days

The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is November (9.3 days).

Average snowfall in December
Chantilly, VA

Average snowfall in December - Chantilly, VA
  • Average snowfall in December: 1.97"

The month with the highest snowfall is January (3.58").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
Chantilly, VA

Average snowfall days in December - Chantilly, VA
  • Average snowfall days in December: 2.7 days

The month with the highest number of snowfall days is February (5.3 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
Chantilly, VA

Average daylight in December / Average sunshine in December - Chantilly, 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 1min

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 6min).

Average sunshine days in December
Chantilly, VA

Average sunshine days in December - Chantilly, VA
  • Average sunshine days in December: 17.8 days

The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is July (12.1 days).

Average UV index in December
Chantilly, VA

Average UV index in December - Chantilly, 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
Chantilly, VA

Average cloud cover in December - Chantilly, VA
  • Average cloud cover in December: 46

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

Average visibility in December
Chantilly, VA

Average visibility in December - Chantilly, VA
  • Average visibility in December: 6mi

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

Chantilly, Virginia, USA

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