December weather forecast
Demarest, NJ

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Weather in December

December, the first month of the winter in Demarest, is also an icy month, with an average temperature ranging between max 41.7°F (5.4°C) and min 30.9°F (-0.6°C).

Temperature

With the beginning of December, the average high-temperature shows a decrease, transitioning from a cool 50.9°F (10.5°C) in November to an icy 41.7°F (5.4°C). December nights experience a consistent temperature drop to a subzero cold 30.9°F (-0.6°C).

Humidity

In December, the average relative humidity is 76%.

Rainfall

The month with the most rainfall in Demarest is December, when the rain falls for 10.7 days and typically aggregates up to 3.46" (88mm) of precipitation.

Snowfall

January through April, November and December are months with snowfall. In Demarest, in December, during 4.6 snowfall days, 1.93" (49mm) of snow is typically accumulated. In Demarest, during the entire year, snow falls for 25.5 days and aggregates up to 10.55" (268mm) 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 7:01 am and sunset at 4:28 pm. On the last day of the month, sunrise is at 7:20 am and sunset at 4:37 pm EST.

Sunshine

The average sunshine in December is 4.7h.

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 reading of 2, and below, represents a low health risk from unsafe exposure to UV radiation for average individuals.
Note: The daily high UV index of 2 during December translates into the following recommendations:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
Updated: Aug 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is December cold?

The high-temperature, in December, in Demarest, records 41.7°F (5.4°C), while the low-temperature is 30.9°F (-0.6°C). In August, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is computed to be 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 76%.

What is the wettest month?

The month with the most rainfall is December, when the rain falls for 10.7 days and typically aggregates up to 3.46" (88mm) of precipitation.

How many days does it rain in December in Demarest?

In Demarest, in December, it is raining for 10.7 days, with typically 3.46" (88mm) of accumulated precipitation.

How much does it snow in December?

In December, it is snowing for 4.6 days. Throughout December, 1.93" (49mm) of snow is accumulated.

What is the month with the shortest days in Demarest?

The month with the shortest days is December, with an average of 9h and 18min of daylight.

How many hours of daylight does Demarest have in December?

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

What time are sunrise and sunset in December in Demarest?

In December, on the first day of the month, sunrise is at 7:01 am and sunset at 4:28 pm. On the last day of the month, sunrise is at 7:20 am and sunset at 4:37 pm EST.

How long on average sun shines in December?

In Demarest, the average sunshine duration in December is 4.7h.

What is the month with 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.

What is the UV index intensity in December?

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 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
Demarest, NJ

Average temperature in December - Demarest, NJ
  • Average high temperature in December: 41.7°F

The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (35.4°F).

  • Average low temperature in December: 30.9°F

The month with the highest average low temperature is July (68°F).
The coldest month (with the lowest average low temperature) is January (24.1°F).

Average pressure in December
Demarest, NJ

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

The month with the highest atmospheric pressure is November (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Demarest, NJ

Average wind speed in December - Demarest, NJ
  • Average wind speed in December: 8mph

The windiest months (with the highest average wind speed) are January and March (8.5mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).

Average humidity in December
Demarest, NJ

Average humidity in December - Demarest, NJ
  • Average humidity in December: 76%

The month with the highest relative humidity is February (77%).
The month with the lowest relative humidity is August (68%).

Average rainfall in December
Demarest, NJ

Average rainfall in December - Demarest, NJ
  • Average rainfall in December: 3.46"

The wettest month (with the highest rainfall) is December (3.46").
The driest month (with the least rainfall) is September (1.73").

Average rainfall days in December
Demarest, NJ

Average rainfall days in December - Demarest, NJ
  • Average rainfall days in December: 10.7 days

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (8.2 days).

Average snowfall in December
Demarest, NJ

Average snowfall in December - Demarest, NJ
  • Average snowfall in December: 1.93"

The month with the highest snowfall is March (3.07").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
Demarest, NJ

Average snowfall days in December - Demarest, NJ
  • Average snowfall days in December: 4.6 days

The month with the highest number of snowfall days is January (6.9 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
Demarest, NJ

Average daylight in December / Average sunshine in December - Demarest, 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 4min

The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in December
Demarest, NJ

Average sunshine days in December - Demarest, NJ
  • Average sunshine days in December: 16.8 days

The months with the most sunshine days are January and November (18.1 days).
The months with the least sunshine days are April and June (12.7 days).

Average UV index in December
Demarest, NJ

Average UV index in December - Demarest, 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
Demarest, NJ

Average cloud cover in December - Demarest, NJ
  • Average cloud cover in December: 49

The months with the most cloud cover are February, March and December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 32).

Average visibility in December
Demarest, NJ

Average visibility in December - Demarest, NJ
  • 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).

Demarest, New Jersey, USA

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