December weather forecast
Jarrettsville, MD

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Weather in December

The first month of the winter, December, is also a frosty month in Jarrettsville, Maryland, with an average temperature varying between 43.7°F (6.5°C) and 32.2°F (0.1°C).

Temperature

A decrease in the average high-temperature is observed during December, shifting from a fresh 52.9°F (11.6°C) in November to a chilly 43.7°F (6.5°C). An average low-temperature of 32.2°F (0.1°C) is recorded during the nights in December.

Humidity

In Jarrettsville, the average relative humidity in December is 78%.

Rainfall

In Jarrettsville, in December, it is raining for 9.8 days, with typically 2.76" (70mm) of accumulated precipitation. In Jarrettsville, during the entire year, the rain falls for 155.7 days and collects up to 32.64" (829mm) of precipitation.

Snowfall

Months with snowfall are January through May, November and December. In Jarrettsville, in December, during 3.4 snowfall days, 1.38" (35mm) of snow is typically accumulated. In Jarrettsville, during the entire year, snow falls for 19.9 days and aggregates up to 9.72" (247mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9h and 24min of daylight.
On the first day of December, sunrise is at 7:08 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:52 pm EST.

Sunshine

In December, the average sunshine is 5h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the average person.
Note: The maximum UV index, 2 during December, leads to the following recommendations:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
Updated: Jun 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is December cold?

The high-temperature during December is 43.7°F (6.5°C) and the low-temperature is 32.2°F (0.1°C). In August, the average heat index (a.k.a. 'real feel', 'felt air temperature'), which factors the actual air temperature with the relative humidity, is appraised at 87.8°F (31°C).

What is the average humidity in December?

In Jarrettsville, the average relative humidity in December is 78%.

How many days does it rain in December?

In Jarrettsville, in December, during 9.8 rainfall days, 2.76" (70mm) of precipitation is typically accumulated.

How many days does it snow in December?

In December, it is snowing for 3.4 days. Throughout December, 1.38" (35mm) of snow is accumulated.

What is the month with the shortest days in Jarrettsville?

With an average of 9h and 24min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

In December, the average day length is 9h and 26min.

When are sunrise and sunset in December in Jarrettsville?

On the first day of December in Jarrettsville, sunrise is at 7:08 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 4:52 pm EST.

How long on average sun shines in December?

The average sunshine duration in December is 5h.

When is the lowest UV index in Jarrettsville?

January, February, November 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?

The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a low health threat from unsafe exposure to Sun's UV rays.
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
Jarrettsville, MD

Average temperature in December - Jarrettsville, MD
  • Average high temperature in December: 43.7°F

The warmest month (with the highest average high temperature) is July (84.6°F).
The month with the lowest average high temperature is January (37.6°F).

  • Average low temperature in December: 32.2°F

The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (25.3°F).

Average pressure in December
Jarrettsville, MD

Average pressure in December - Jarrettsville, MD
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in December
Jarrettsville, MD

Average wind speed in December - Jarrettsville, MD
  • Average wind speed in December: 8.3mph

The windiest month (with the highest average wind speed) is March (9.1mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).

Average humidity in December
Jarrettsville, MD

Average humidity in December - Jarrettsville, MD
  • Average humidity in December: 78%

The month with the highest relative humidity is May (80%).
The month with the lowest relative humidity is April (74%).

Average rainfall in December
Jarrettsville, MD

Average rainfall in December - Jarrettsville, MD
  • Average rainfall in December: 2.76"

The wettest month (with the highest rainfall) is August (4.09").
The driest month (with the least rainfall) is February (2.09").

Average rainfall days in December
Jarrettsville, MD

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

The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is January (8.3 days).

Average snowfall in December
Jarrettsville, MD

Average snowfall in December - Jarrettsville, MD
  • Average snowfall in December: 1.38"

The month with the highest snowfall is March (2.87").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in December
Jarrettsville, MD

Average snowfall days in December - Jarrettsville, MD
  • Average snowfall days in December: 3.4 days

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

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

Average daylight in December / Average sunshine in December - Jarrettsville, MD
  • Average daylight in December: 9h and 2min

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 24min).

  • Average sunshine in December: 5h and 0min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).

Average sunshine days in December
Jarrettsville, MD

Average sunshine days in December - Jarrettsville, MD
  • Average sunshine days in December: 17.8 days

The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is May (11.7 days).

Average UV index in December
Jarrettsville, MD

Average UV index in December - Jarrettsville, 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).

Average cloud cover in December
Jarrettsville, MD

Average cloud cover in December - Jarrettsville, 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).

Average visibility in December
Jarrettsville, MD

Average visibility in December - Jarrettsville, 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).

Jarrettsville, Maryland, USA

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