December weather forecast and climate
Mahwah, NJ

Weather in December

The first month of the winter, December, is still a cold month in Mahwah, New Jersey, with average temperature fluctuating between 29.1°F (-1.6°C) and 40.1°F (4.5°C).

Temperature

In December, the average high-temperature decreases, from a cool 50°F (10°C) in November, to a wintry 40.1°F (4.5°C). In Mahwah, New Jersey, in December, the average low-temperature is 29.1°F (-1.6°C).

Humidity

February and December, with an average relative humidity of 79%, are most humid months.

Rainfall

The month with the most rainfall is December when the rain falls for 10.8 days and typically aggregates up to 2.68" (68mm) of precipitation.

Snowfall

Months with snowfall in Mahwah are January through May, October through December. In Mahwah, in December, during 5.1 snowfall days, 1.81" (46mm) of snow is typically accumulated. In Mahwah, during the entire year, snow falls for 28.5 days, and aggregates up to 10.98" (279mm) of snow.

Daylight

With an average of 9.3h of daylight, December has the shortest days of the year in Mahwah, New Jersey.

Sunshine

The average sunshine in Mahwah is 4.8h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Mahwah. A UV Index of 2, and less, symbolizes a minimal health vulnerability from the exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 2 in December transform into the following instructions:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in December in Mahwah?

In December, in Mahwah, New Jersey, the average high-temperature is 40.1°F (4.5°C), and the average low-temperature is 29.1°F (-1.6°C).

What is the most humid month in Mahwah?

Months with the highest humidity in Mahwah are February and December, with an average relative humidity of 79%.

What is the average humidity in December in Mahwah?

The average relative humidity in December is 79%.

How much does it rain in Mahwah in December?

In Mahwah, in December, during 10.8 rainfall days, 2.68" (68mm) of precipitation is typically accumulated.

What is the wettest month in Mahwah?

The month with the most rainfall is December when the rain falls for 10.8 days and typically aggregates up to 2.68" (68mm) of precipitation.

How many days does it snow in December in Mahwah?

In Mahwah, New Jersey, in December, snow falls for 5.1 days, with typically accumulated 1.81" (46mm) of snow.

What is the month with the shortest days in Mahwah?

The month with the shortest days is December, with an average of 9.3h of daylight.

How many hours of daylight does Mahwah have in December?

In Mahwah, the average length of the day in December is 9.3h.

How long on average sun shines in December in Mahwah?

In Mahwah, the average sunshine in December is 4.8h.

When is the lowest UV index in Mahwah?

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

What is the UV index intensity in December in Mahwah?

In Mahwah, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low health threat from unprotected exposure to the UV radiation.

Average temperature in December
Mahwah, NJ

Average temperature in December - Mahwah, NJ
  • Average high temperature in December: 40.1°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 (34.3°F).

  • Average low temperature in December: 29.1°F

The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (21.7°F).

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Average pressure in December
Mahwah, NJ

Average pressure in December - Mahwah, NJ
  • Average pressure in December: 30.07"

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

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Average wind speed in December
Mahwah, NJ

Average wind speed in December - Mahwah, NJ
  • Average wind speed in December: 7.1mph

The windiest month (with the highest average wind speed) is March (7.7mph).
The calmest month (with the lowest average wind speed) is August (5mph).

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Average humidity in December
Mahwah, NJ

Average humidity in December - Mahwah, NJ
  • Average humidity in December: 79%

Months with the highest relative humidity are February and December (79%).
The month with the lowest relative humidity is April (72%).

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Average rainfall in December
Mahwah, NJ

Average rainfall in December - Mahwah, NJ
  • Average rainfall in December: 2.68"

The wettest month (with the highest rainfall) is December (2.68").
The driest month (with the least rainfall) is September (1.34").

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Average rainfall days in December
Mahwah, NJ

Average rainfall days in December - Mahwah, NJ
  • Average rainfall days in December: 10.8 days

The month with the highest number of rainy days is July (16.6 days).
The month with the least rainy days is January (7.8 days).

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Average snowfall in December
Mahwah, NJ

Average snowfall in December - Mahwah, NJ
  • Average snowfall in December: 1.81"

The month with the highest snowfall is February (2.91").
Months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Mahwah, NJ

Average snowfall days in December - Mahwah, NJ
  • Average snowfall days in December: 5.1 days

The month with the highest number of snowfall days is February (7.7 days).
Months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Mahwah, NJ
  • Average daylight in December: 9.3h

The month with the longest days is June (Average daylight: 15.1h).
The month with the shortest days is December (Average daylight: 9.3h).

  • Average sunshine in December: 4.8h

The month with the most sunshine is July (Average sunshine: 10.4h).
The month with the least sunshine is February (Average sunshine: 4.5h).

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Average sunshine days in December
Mahwah, NJ

Average sunshine days in December - Mahwah, 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 (11.8 days).

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Average UV index in December
Mahwah, NJ

Average UV index in December - Mahwah, NJ
  • Average UV index in December: 2

Months with the highest UV index are June, July and August (UV index 6).
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
Mahwah, NJ

Average cloud cover in December - Mahwah, NJ
  • Average cloud cover in December: 48

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

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Average visibility in December
Mahwah, NJ

Average visibility in December - Mahwah, NJ
  • Average visibility in December: 6mi

Months with the highest visibility are January, March, April, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are February and May (5mi).

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