December weather forecast
Greenbelt, MD

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Weather in December

The final month, December, rolls out a beautiful wintry scene for Greenbelt, marked by the year's shortest daylight hours, 9.5 hours. As the region readies to bid adieu to the year, the unmistakable signs of winter peek in with a moderate snowfall of 0.67" (17mm). The crisp winter air, dense foggy mornings, and potential for snowfall create a mystical aura that cloaks the city, rounding off the year on a beautiful note.

Temperature

The arrival of December corresponds with a light shift in temperature, down from a cool 54.1°F (12.3°C) in November to a chilly 45.5°F (7.5°C). December's nights observe an average temperature of 34.3°F (1.3°C).

Humidity

May, October and December, with an average relative humidity of 76%, are the most humid months.

Rainfall

In Greenbelt, during December, the rain falls for 9.8 days and regularly aggregates up to 2.6" (66mm) of precipitation. Throughout the year, there are 157.9 rainfall days, and 31.14" (791mm) of precipitation is accumulated.

Snowfall

January through April and December are months with snowfall. December is the first month it typically snows in Greenbelt. Throughout December, in the average 2.4 snowfall days, it receives 0.67" (17mm) of snow. Throughout the year, there are 13.5 snowfall days, and 7.2" (183mm) 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 7:07 am and sunset at 4:45 pm. On the last day of December, sunrise is at 7:26 am and sunset at 4:55 pm EST.

Sunshine

In December, the average sunshine is 5.1h.

UV index

January and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to UV radiation for average individuals.
Note: In December, a regular UV index of 2 translates into these guidelines:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.

Frequently asked questions

What are the temperatures in Greenbelt in December?

December temperatures vary between a high-temperature of 45.5°F (7.5°C) and a low-temperature of 34.3°F (1.3°C). In August, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines relative humidity and air temperature, is computed to be 93.2°F (34°C).

What is the most humid month?

May, October and December, with an average relative humidity of 76%, are most humid months.

What is the average humidity in December in Greenbelt?

The average relative humidity in December is 76%.

How many days does it rain in December?

In December, the rain falls for 9.8 days. Throughout December, 2.6" (66mm) of precipitation is accumulated.

When does it start to snow?

December is the first month it typically snows. Throughout December, in the average 2.4 snowfall days, it receives 0.67" (17mm) of snow.

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.

How many hours of daylight does Greenbelt have in December?

The average day length in December is 9h and 29min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:07 am and sunset at 4:45 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:55 pm EST.

How many hours of sunshine does Greenbelt have in December?

The average sunshine duration in December is 5.1h.

What is the month with the lowest UV index?

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

What is the UV index reading in December?

In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes 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
Greenbelt, MD

Average temperature in December - Greenbelt, MD
  • Average high temperature in December: 45.5°F

The warmest month (with the highest average high temperature) is July (87.4°F).
The month with the lowest average high temperature is January (39.9°F).

  • Average low temperature in December: 34.3°F

The month with the highest average low temperature is July (70°F).
The coldest month (with the lowest average low temperature) is January (27.7°F).

Average pressure in December
Greenbelt, MD

Average pressure in December - Greenbelt, MD
  • 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 (29.94"Hg).

Average wind speed in December
Greenbelt, MD

Average wind speed in December - Greenbelt, MD
  • Average wind speed in December: 7.3mph

The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

Average humidity in December
Greenbelt, MD

Average humidity in December - Greenbelt, MD
  • Average humidity in December: 76%

The months with the highest relative humidity are May, October and December (76%).
The months with the lowest relative humidity are April and July (71%).

Average rainfall in December
Greenbelt, MD

Average rainfall in December - Greenbelt, MD
  • Average rainfall in December: 2.6"

The wettest month (with the highest rainfall) is August (3.58").
The driest month (with the least rainfall) is January (2.01").

Average rainfall days in December
Greenbelt, MD

Average rainfall days in December - Greenbelt, MD
  • Average rainfall days in December: 9.8 days

The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is November (9 days).

Average snowfall in December
Greenbelt, MD

Average snowfall in December - Greenbelt, MD
  • Average snowfall in December: 0.67"

The month with the highest snowfall is January (2.6").
The months with the least snowfall are May, June, July, August, September, October and November (0").

Average snowfall days in December
Greenbelt, MD

Average snowfall days in December - Greenbelt, MD
  • Average snowfall days in December: 2.4 days

The month with the highest number of snowfall days is January (4.1 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
Greenbelt, MD

Average daylight in December / Average sunshine in December - Greenbelt, MD
  • 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 54min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).

Average sunshine days in December
Greenbelt, MD

Average sunshine days in December - Greenbelt, MD
  • Average sunshine days in December: 18.1 days

The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is May (11.8 days).

Average UV index in December
Greenbelt, MD

Average UV index in December - Greenbelt, MD
  • 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 and December (UV index 2).

Average cloud cover in December
Greenbelt, MD

Average cloud cover in December - Greenbelt, MD
  • Average cloud cover in December: 45

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 29).

Average visibility in December
Greenbelt, MD

Average visibility in December - Greenbelt, MD
  • Average visibility in December: 6mi

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

Greenbelt, Maryland, USA

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