December weather forecast
Glen Rock, NJ

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Weather in December

The first month of the winter, December, is also an icy month in Glen Rock, New Jersey, with an average temperature varying between 30.9°F (-0.6°C) and 41.2°F (5.1°C).

Temperature

In Glen Rock, the beginning of December is marked by a lowered average high-temperature, shifting from November's fresh 50.9°F (10.5°C) to an icy 41.2°F (5.1°C). December brings Glen Rock a consistent average low-temperature of 30.9°F (-0.6°C).

Humidity

February and December, with an average relative humidity of 78%, are the most humid months.

Rainfall

The wettest months are July and December, with an average 3.07" (78mm) of rainfall.

Snowfall

Months with snowfall are January through May, October through December. In Glen Rock, in December, snow falls for 4 days, with typically accumulated 1.54" (39mm) of snow. In Glen Rock, during the entire year, snow falls for 24.9 days and aggregates up to 10.04" (255mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9h and 18min of daylight.
On the first day of December, sunrise is at 7:02 am and sunset at 4:29 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:38 pm EST.

Sunshine

In December, the average sunshine is 4.8h.

UV index

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to UV radiation for the average person.
Note: An average UV index of 2 in December transforms into this advice:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.
Updated: Jul 27, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is it cold during December?

In December, the average high-temperature and low-temperature are 41.2°F (5.1°C) and 30.9°F (-0.6°C) respectively. In August, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines relative humidity and air temperature, is appraised at 87.8°F (31°C).

What is the most humid month?

February and December, with an average relative humidity of 78%, are most humid months in Glen Rock, New Jersey.

What is the average humidity in December?

In December, the average relative humidity is 78%.

What is the wettest month?

The wettest months are July and December, with an average 3.07" (78mm) of rainfall.

How much does it rain in December?

In December, the rain falls for 11.2 days. Throughout December, 3.07" (78mm) of precipitation is accumulated.

How much does it snow in December?

In December, it is snowing for 4 days. Throughout December, 1.54" (39mm) of snow is accumulated.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 18min of daylight.

How many hours of daylight does Glen Rock have in December?

In December, the average day length is 9h and 17min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:02 am and sunset at 4:29 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:38 pm EST.

How many hours of sunshine does Glen Rock have in December?

The average sunshine duration in December is 4.8h.

When is the lowest UV index?

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

How high is the UV index in December?

The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability 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
Glen Rock, NJ

Average temperature in December - Glen Rock, NJ
  • Average high temperature in December: 41.2°F

The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (35.2°F).

  • Average low temperature in December: 30.9°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 (23.4°F).

Average pressure in December
Glen Rock, NJ

Average pressure in December - Glen Rock, NJ
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Glen Rock, NJ

Average wind speed in December - Glen Rock, NJ
  • Average wind speed in December: 7.8mph

The windiest month (with the highest average wind speed) is March (8.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).

Average humidity in December
Glen Rock, NJ

Average humidity in December - Glen Rock, NJ
  • Average humidity in December: 78%

The months with the highest relative humidity are February and December (78%).
The months with the lowest relative humidity are April, July and August (72%).

Average rainfall in December
Glen Rock, NJ

Average rainfall in December - Glen Rock, NJ
  • Average rainfall in December: 3.07"

The wettest months (with the highest rainfall) are July and December (3.07").
The driest month (with the least rainfall) is September (1.73").

Average rainfall days in December
Glen Rock, NJ

Average rainfall days in December - Glen Rock, NJ
  • Average rainfall days in December: 11.2 days

The month with the highest number of rainy days is June (17 days).
The month with the least rainy days is January (8.9 days).

Average snowfall in December
Glen Rock, NJ

Average snowfall in December - Glen Rock, NJ
  • Average snowfall in December: 1.54"

The month with the highest snowfall is February (3.23").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Glen Rock, NJ

Average snowfall days in December - Glen Rock, NJ
  • Average snowfall days in December: 4 days

The month with the highest number of snowfall days is February (7.2 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Glen Rock, NJ

Average daylight in December / Average sunshine in December - Glen Rock, NJ
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 4h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in December
Glen Rock, NJ

Average sunshine days in December - Glen Rock, NJ
  • Average sunshine days in December: 15.7 days

The month with the most sunshine days is November (18.8 days).
The month with the least sunshine days is June (10.5 days).

Average UV index in December
Glen Rock, NJ

Average UV index in December - Glen Rock, NJ
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in December
Glen Rock, NJ

Average cloud cover in December - Glen Rock, NJ
  • Average cloud cover in December: 48

The month with the most cloud cover is March (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 33).

Average visibility in December
Glen Rock, NJ

Average visibility in December - Glen Rock, NJ
  • 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).

Glen Rock, New Jersey, USA

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