December weather forecastGreat Falls, VA
December
Weather in December
The first month of the winter, December, is still a chilly month in Great Falls, Virginia, with temperature in the range of an average low of 32.7°F (0.4°C) and an average high of 45.3°F (7.4°C).Temperature
Great Falls's weather subtly changes with the onset of December, barely falling from a fresh 53.4°F (11.9°C) in November to a frosty 45.3°F (7.4°C). Great Falls's temperature lowers to a mean of 32.7°F (0.4°C) during the nights in December.Humidity
October and December, with an average relative humidity of 76%, are the most humid months in Great Falls, Virginia.Rainfall
In Great Falls, during December, the rain falls for 9.8 days and regularly aggregates up to 2.17" (55mm) of precipitation. Throughout the year, there are 152.8 rainfall days, and 27.64" (702mm) of precipitation is accumulated.Snowfall
January through April, November and December are months with snowfall. In Great Falls, in December, during 2.2 snowfall days, 1.22" (31mm) of snow is typically accumulated. In Great Falls, during the entire year, snow falls for 13.9 days and aggregates up to 7.2" (183mm) 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
The months with the least sunshine are January, February and December, with an average of 5h 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 estimate of 2, and below, represents a minimal health hazard from unsafe exposure to UV radiation for average individuals.Note: A maximum high daily UV index of 2 during December translates into the following directions:
Children necessitate constant protection from sunlight, unlike the majority, who can remain under the sun for about an hour without burning. Direct Sun exposure should be minimized especially during midday when radiation is most intense. During bright days, sunglasses that offer UVA and UVB defense are recommended. Watch out! The Sun's UV radiation can be nearly magnified twofold due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Great Falls, VA
- Average high temperature in December: 45.3°F
The warmest month (with the highest average high temperature) is July (87.6°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in December: 32.7°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.4°F).
Average pressure in December
Great Falls, 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
Great Falls, VA
- Average wind speed in December: 6.8mph
The windiest month (with the highest average wind speed) is March (7.7mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).
Average humidity in December
Great Falls, VA
- Average humidity in December: 76%
The months with the highest relative humidity are October and December (76%).
The month with the lowest relative humidity is July (69%).
Average rainfall in December
Great Falls, VA
- Average rainfall in December: 2.17"
The wettest month (with the highest rainfall) is August (3.39").
The driest month (with the least rainfall) is January (1.77").
Average rainfall days in December
Great Falls, VA
- Average rainfall days in December: 9.8 days
The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is November (9.3 days).
Average snowfall in December
Great Falls, VA
- Average snowfall in December: 1.22"
The month with the highest snowfall is January (2.28").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Great Falls, VA
- Average snowfall days in December: 2.2 days
The month with the highest number of snowfall days is January (4.6 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
Great Falls, 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
Great Falls, VA
- Average sunshine days in December: 17.9 days
The month with the most sunshine days is November (19.3 days).
The month with the least sunshine days is May (12.8 days).
Average UV index in December
Great Falls, 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
Great Falls, 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
Great Falls, 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).
