December weather forecastMontclair, NJ

December

Weather in December

The first month of the winter, December, is also a wintry month in Montclair, New Jersey, with temperature in the range of an average low of 31.1°F (-0.5°C) and an average high of 41.5°F (5.3°C).

Temperature

With December's arrival, Montclair sees a decrease in average high-temperatures, moving from a cool 50.7°F (10.4°C) in November to a cold 41.5°F (5.3°C). Montclair observes an average low-temperature of 31.1°F (-0.5°C) during December nights.

Humidity

The average relative humidity in December is 77%.

Rainfall

In December, the rain falls for 10.6 days. Throughout December, 2.24" (57mm) of precipitation is accumulated. Throughout the year, in Montclair, there are 153.3 rainfall days, and 24.92" (633mm) of precipitation is accumulated.

Snowfall

January through April, November and December are months with snowfall. In Montclair, during December, snow falls for 3.6 days and regularly aggregates up to 1.18" (30mm) of snow. In Montclair, during the entire year, snow falls for 22.1 days and aggregates up to 8.9" (226mm) 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 the month, sunrise is at 7:02 am and sunset at 4:29 pm. On the last day of December, sunrise is at 7:21 am and sunset at 4:39 pm EST.

Sunshine

In December, the average sunshine is 4.9h.

UV index

The months with the lowest UV index in Montclair 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 exposure to the Sun's UV radiation for the ordinary person.
Note: The average daily UV index of 2 in December transforms into the following instructions:
Prolonged sun exposure should always be prevented in babies, children, and those with sensitive skin. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
Updated: Aug 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

In Montclair, 41.5°F (5.3°C) is the average high-temperature and 31.1°F (-0.5°C) is the average low-temperature during December. The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines relative humidity and air temperature, in August is calculated to be 86°F (30°C).

In December, the average relative humidity is 77%.

In Montclair, in December, it is raining for 10.6 days, with typically 2.24" (57mm) of accumulated precipitation.

In Montclair, during December, snow falls for 3.6 days and regularly aggregates up to 1.18" (30mm) of snow.

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

The average day length in December is 9h and 18min.

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 4:39 pm EST.

In December, the average sunshine duration is 4.9h.

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

The average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a low health risk from exposure to the Sun's UV radiation.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Montclair, NJ

  • Average high temperature in December: 41.5°F

The warmest month (with the highest average high temperature) is July (84.2°F).
The month with the lowest average high temperature is January (35.2°F).

  • Average low temperature in December: 31.1°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 (23.9°F).

Average pressure in December
Montclair, NJ

  • Average pressure in December: 30.08"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
Montclair, NJ

  • Average wind speed in December: 8.1mph

The windiest months (with the highest average wind speed) are January and March (8.8mph).
The calmest month (with the lowest average wind speed) is July (5.7mph).

Average humidity in December
Montclair, NJ

  • Average humidity in December: 77%

The month with the highest relative humidity is February (78%).
The months with the lowest relative humidity are April and August (72%).

Average rainfall in December
Montclair, NJ

  • Average rainfall in December: 2.24"

The wettest month (with the highest rainfall) is July (3.07").
The driest month (with the least rainfall) is January (1.38").

Average rainfall days in December
Montclair, NJ

  • Average rainfall days in December: 10.6 days

The month with the highest number of rainy days is July (17.7 days).
The month with the least rainy days is January (7.6 days).

Average snowfall in December
Montclair, NJ

  • Average snowfall in December: 1.18"

The month with the highest snowfall is March (3.27").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
Montclair, NJ

  • Average snowfall days in December: 3.6 days

The month with the highest number of snowfall days is February (6.8 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
Montclair, NJ

  • Average daylight in December: 9h and 18min

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 54min

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in December
Montclair, NJ

  • Average sunshine days in December: 17.3 days

The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is July (10.7 days).

Average UV index in December
Montclair, 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
Montclair, NJ

  • Average cloud cover in December: 47

The months with the most cloud cover are February and March (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 31).

Average visibility in December
Montclair, 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).