December weather forecast
Marriottsville, MD

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Weather in December

December, the first month of the winter in Marriottsville, is still a chilly month, with temperature in the range of an average low of 31.5°F (-0.3°C) and an average high of 43.5°F (6.4°C).

Temperature

December's onset brings a negligible change in high-temperatures, falling from a cool 52.3°F (11.3°C) in November to a chilly 43.5°F (6.4°C). In the month of December, the temperature generally rests at an average low of 31.5°F (-0.3°C).

Humidity

The average relative humidity in December is 77%.

Rainfall

In Marriottsville, Maryland, during December, the rain falls for 10.5 days and regularly aggregates up to 2.4" (61mm) of precipitation. Throughout the year, in Marriottsville, there are 159 rainfall days, and 31.61" (803mm) of precipitation is accumulated.

Snowfall

January through May, November and December are months with snowfall. In Marriottsville, during December, snow falls for 3.2 days and regularly aggregates up to 1.54" (39mm) of snow. Throughout the year, there are 18.7 snowfall days, and 9.96" (253mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 30min of daylight.
On the first day of December in Marriottsville, Maryland, sunrise is at 7:09 am and sunset at 4:44 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:54 pm EST.

Sunshine

The average sunshine in December is 5.1h.

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 reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: A daily maximum UV index of 2 in December translates into the following instructions:
Children, babies, and those with sensitive skin should always be shielded from long periods of sun exposure. To guard against the harmful effects of the Sun, minimize exposure during midday. Experience reduced UV exposure by about half when donning a wide-brim hat. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
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Frequently asked questions

Is it cold in Marriottsville during December?

An average high-temperature, in December, in Marriottsville, is 43.5°F (6.4°C) and the average low-temperature is 31.5°F (-0.3°C). In August, the average heat index (a.k.a. 'real feel', 'feels like'), which calculates the temperature value influenced by the moisture in the air, is computed to be 89.6°F (32°C).

What is the average humidity in December in Marriottsville?

The average relative humidity in December in Marriottsville, Maryland, is 77%.

How much does it rain in Marriottsville in December?

In Marriottsville, in December, during 10.5 rainfall days, 2.4" (61mm) of precipitation is typically accumulated.

How much does it snow in Marriottsville in December?

In Marriottsville, Maryland, in December, during 3.2 snowfall days, 1.54" (39mm) of snow is typically accumulated.

What is the month with the shortest days in Marriottsville?

December has the shortest days of the year in Marriottsville, with an average of 9h and 30min of daylight.

How many hours of daylight does Marriottsville have in December?

In December, the average day length in Marriottsville, Maryland, is 9h and 27min.

When is the sunrise / sunset in December in Marriottsville?

On the first day of December in Marriottsville, sunrise is at 7:09 am and sunset at 4:44 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:54 pm EST.

How long on average sun shines in December in Marriottsville?

The average sunshine duration in December in Marriottsville, Maryland, is 5.1h.

What are the months with the lowest UV index in Marriottsville?

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

What is the UV index reading in December in Marriottsville?

The average daily maximum UV index in December in Marriottsville is 2. A UV Index value of 2, and less, symbolizes a low health threat from unprotected exposure to 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
Marriottsville, MD

Average temperature in December - Marriottsville, MD
  • Average high temperature in December: 43.5°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (37.6°F).

  • Average low temperature in December: 31.5°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (25°F).

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Average pressure in December
Marriottsville, MD

Average pressure in December - Marriottsville, 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).

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Average wind speed in December
Marriottsville, MD

Average wind speed in December - Marriottsville, MD
  • Average wind speed in December: 8mph

The windiest month (with the highest average wind speed) is March (8.8mph).
The calmest months (with the lowest average wind speed) are July and August (5.3mph).

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Average humidity in December
Marriottsville, MD

Average humidity in December - Marriottsville, MD
  • Average humidity in December: 77%

The month with the highest relative humidity is May (79%).
The months with the lowest relative humidity are April and July (74%).

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Average rainfall in December
Marriottsville, MD

Average rainfall in December - Marriottsville, MD
  • Average rainfall in December: 2.4"

The wettest month (with the highest rainfall) is August (3.9").
The driest month (with the least rainfall) is February (1.97").

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Average rainfall days in December
Marriottsville, MD

Average rainfall days in December - Marriottsville, MD
  • Average rainfall days in December: 10.5 days

The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is January (8.6 days).

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Average snowfall in December
Marriottsville, MD

Average snowfall in December - Marriottsville, MD
  • Average snowfall in December: 1.54"

The month with the highest snowfall is March (2.8").
The months with the least snowfall are June, July, August, September and October (0").

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Average snowfall days in December
Marriottsville, MD

Average snowfall days in December - Marriottsville, MD
  • Average snowfall days in December: 3.2 days

The month with the highest number of snowfall days is January (5.6 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
Marriottsville, MD

Average daylight in December / Average sunshine in December - Marriottsville, 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 36min).
The months with the least sunshine are January and February (Average sunshine: 4h and 48min).

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Average sunshine days in December
Marriottsville, MD

Average sunshine days in December - Marriottsville, MD
  • Average sunshine days in December: 17.4 days

The month with the most sunshine days is November (18.8 days).
The month with the least sunshine days is May (11.2 days).

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Average UV index in December
Marriottsville, MD

Average UV index in December - Marriottsville, 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, February, November and December (UV index 2).

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Average cloud cover in December
Marriottsville, MD

Average cloud cover in December - Marriottsville, MD
  • Average cloud cover in December: 46

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
Marriottsville, MD

Average visibility in December - Marriottsville, MD
  • 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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Marriottsville, Maryland, USA

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