December weather forecast
Rockleigh, NJ

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Weather in December

The first month of the winter, December, is also a wintry month in Rockleigh, New Jersey, with an average temperature ranging between max 41.7°F (5.4°C) and min 30.9°F (-0.6°C).

Temperature

December shows a mild decline in the average high-temperature, falling from November's fresh 50.9°F (10.5°C) to a wintry 41.7°F (5.4°C). Nightly temperatures in Rockleigh drop to an average low of 30.9°F (-0.6°C) in December.

Humidity

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

Rainfall

The month with the most rainfall in Rockleigh 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 December, in Rockleigh, New Jersey, it is snowing for 4.6 days. Throughout December, 1.93" (49mm) of snow is accumulated. Throughout the year, in Rockleigh, there are 25.5 snowfall days, and 10.55" (268mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 18min of daylight.
On the first day of the month, sunrise is at 7:01 am and sunset at 4:28 pm. On the last day of December, in Rockleigh, sunrise is at 7:20 am and sunset at 4:37 pm EST.

Sunshine

In December, the average sunshine in Rockleigh 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 of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: An average maximum UV index of 2 in December leads to these recommendations:
Despite most people tolerating extended sun exposure, it is critical to always protect those with sensitive skin, infants, and children. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
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Frequently asked questions

How cold is it in Rockleigh in December?

In Rockleigh, 41.7°F (5.4°C) is the average high-temperature and 30.9°F (-0.6°C) is the average low-temperature during December. The average heat index (a.k.a. 'feels like', 'apparent temperature'), which combines air temperature and relative humidity, in August is appraised at 87.8°F (31°C).

What is the average humidity in December in Rockleigh?

In Rockleigh, New Jersey, the average relative humidity in December is 76%.

What is the rainiest month in Rockleigh?

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

How much does it rain in Rockleigh in December?

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

How much does it snow in Rockleigh in December?

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

What is the month with the shortest days in Rockleigh?

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

What is the average length of the day in December in Rockleigh?

The average day length in December is 9h and 17min.

When is the sunrise / sunset in December in Rockleigh?

On the first day of December in Rockleigh, 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 many hours of sunshine does Rockleigh have in December?

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

When is the lowest UV index in Rockleigh?

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

How high is the UV index in December in Rockleigh?

In December, the average daily maximum UV index is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability 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
Rockleigh, NJ

Average temperature in December - Rockleigh, 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).

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Average pressure in December
Rockleigh, NJ

Average pressure in December - Rockleigh, 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).

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Average wind speed in December
Rockleigh, NJ

Average wind speed in December - Rockleigh, 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).

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Average humidity in December
Rockleigh, NJ

Average humidity in December - Rockleigh, 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%).

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Average rainfall in December
Rockleigh, NJ

Average rainfall in December - Rockleigh, 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").

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Average rainfall days in December
Rockleigh, NJ

Average rainfall days in December - Rockleigh, 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).

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Average snowfall in December
Rockleigh, NJ

Average snowfall in December - Rockleigh, 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").

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Average snowfall days in December
Rockleigh, NJ

Average snowfall days in December - Rockleigh, 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).

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Average daylight in December /
Average sunshine in December
Rockleigh, NJ

Average daylight in December / Average sunshine in December - Rockleigh, 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).

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Average sunshine days in December
Rockleigh, NJ

Average sunshine days in December - Rockleigh, 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).

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Average UV index in December
Rockleigh, NJ

Average UV index in December - Rockleigh, 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).

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Average cloud cover in December
Rockleigh, NJ

Average cloud cover in December - Rockleigh, 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).

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Average visibility in December
Rockleigh, NJ

Average visibility in December - Rockleigh, 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).

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Rockleigh, New Jersey, USA

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