December weather forecast
River Vale, NJ

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Weather in December

December, the first month of the winter in River Vale, is still a cold month, with an average temperature fluctuating between 30.9°F (-0.6°C) and 41.7°F (5.4°C).

Temperature

With the beginning of December, the average high-temperature shows a decrease, transitioning from a fresh 50.9°F (10.5°C) in November to a wintry 41.7°F (5.4°C). River Vale experiences an average nighttime temperature of 30.9°F (-0.6°C) in the month of December.

Humidity

In River Vale, the average relative humidity in December is 76%.

Rainfall

The month with the most rainfall in River Vale 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 River Vale, New Jersey, in December, during 4.6 snowfall days, 1.93" (49mm) of snow is typically accumulated. In River Vale, during the entire year, snow falls for 25.5 days and aggregates up to 10.55" (268mm) of snow.

Daylight

With an average of 9h and 18min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:02 am and sunset at 4:28 pm. On the last day of December, sunrise is at 7:20 am and sunset at 4:37 pm EST.

Sunshine

In December, the average sunshine is 4.7h.

UV index

January through March, 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 exposure to the Sun's UV rays for the ordinary person.
Note: The UV index of 2 in December translates into these instructions:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. Always opt for UVA and UVB-resistant sunglasses on radiant days. Note well! The intensity of the Sun's UV rays can be nearly doubled by snow reflection.
Updated: Jul 31, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold does it get in December?

The average high-temperature and low-temperature during December are 41.7°F (5.4°C) and 30.9°F (-0.6°C) respectively. In August, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which factors the actual air temperature with the relative humidity, is calculated 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 River Vale, in December, during 10.7 rainfall days, 3.46" (88mm) of precipitation is typically accumulated.

How many days does it snow in December?

In River Vale, in December, during 4.6 snowfall days, 1.93" (49mm) of snow is typically accumulated.

What is the month with the shortest days?

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

How many hours of daylight does River Vale have in December?

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

When is the sunrise / sunset in December in River Vale?

In December, on the first day of the month, sunrise is at 7:02 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 many hours of sunshine does River Vale have in December?

In River Vale, New Jersey, the average sunshine duration in December is 4.7h.

What are the months 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 of 2, and less, symbolizes a minimal hazard to health from 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
River Vale, NJ

Average temperature in December - River Vale, 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
River Vale, NJ

Average pressure in December - River Vale, 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
River Vale, NJ

Average wind speed in December - River Vale, 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
River Vale, NJ

Average humidity in December - River Vale, 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
River Vale, NJ

Average rainfall in December - River Vale, 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
River Vale, NJ

Average rainfall days in December - River Vale, 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
River Vale, NJ

Average snowfall in December - River Vale, 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
River Vale, NJ

Average snowfall days in December - River Vale, 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
River Vale, NJ

Average daylight in December / Average sunshine in December - River Vale, 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
River Vale, NJ

Average sunshine days in December - River Vale, 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
River Vale, NJ

Average UV index in December - River Vale, 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
River Vale, NJ

Average cloud cover in December - River Vale, 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
River Vale, NJ

Average visibility in December - River Vale, 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).

River Vale, New Jersey, USA

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