December weather forecast
South Plainfield, NJ

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Weather in December

The first month of the winter, December, is still a cold month in South Plainfield, New Jersey, with temperature in the range of an average high of 42.3°F (5.7°C) and an average low of 31.1°F (-0.5°C).

Temperature

In December, the meteorological conditions change slightly, with the average high-temperature moving from a fresh 51.1°F (10.6°C) in November to an icy 42.3°F (5.7°C). The temperature dips to an average of 31.1°F (-0.5°C) during December nights.

Humidity

The months with the highest humidity are February, October and December, with an average relative humidity of 78%.

Rainfall

December is the month with the most rainfall. Rain falls for 11.5 days and accumulates 3.19" (81mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. In December, it is snowing for 4.1 days. Throughout December, 1.46" (37mm) of snow is accumulated. In South Plainfield, during the entire year, snow falls for 25.4 days and aggregates up to 10.31" (262mm) of snow.

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 7:02 am and sunset at 4:31 pm. On the last day of December, in South Plainfield, sunrise is at 7:21 am and sunset at 4:40 pm EST.

Sunshine

In South Plainfield, New Jersey, the average sunshine in December is 4.9h.

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 value of 2, and less, symbolizes a low health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In December, an average UV index of 2 transforms into the following instructions:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Note this! The Sun's UV radiation can nearly be doubled by the reflection off snow.
Updated: Jul 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in South Plainfield in December?

In December, in South Plainfield, the average high-temperature is 42.3°F (5.7°C), and the average low-temperature is 31.1°F (-0.5°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which calculates the temperature value influenced by the moisture in the air, in August is calculated to be 87.8°F (31°C).

What is the most humid month?

The months with the highest humidity are February, October and December, with an average relative humidity of 78%.

What is the average humidity in December?

In South Plainfield, the average relative humidity in December is 78%.

What is the rainiest month?

December is the month with the most rainfall. Rain falls for 11.5 days and accumulates 3.19" (81mm) of precipitation.

How many days does it rain in December?

In South Plainfield, in December, during 11.5 rainfall days, 3.19" (81mm) of precipitation is typically accumulated.

How many days does it snow in December?

In South Plainfield, in December, snow falls for 4.1 days, with typically accumulated 1.46" (37mm) of snow.

What is the month with the shortest days in South Plainfield?

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

How many hours of daylight does South Plainfield have in December?

The average day length in December is 9h and 20min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 7:02 am and sunset at 4:31 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:40 pm EST.

How long on average sun shines in December?

In December, the average sunshine duration in South Plainfield is 4.9h.

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 reading in December?

In December, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a low health threat 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
South Plainfield, NJ

Average temperature in December - South Plainfield, NJ
  • Average high temperature in December: 42.3°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 (36°F).

  • Average low temperature in December: 31.1°F

The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (23.9°F).

Average pressure in December
South Plainfield, NJ

Average pressure in December - South Plainfield, 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
South Plainfield, NJ

Average wind speed in December - South Plainfield, NJ
  • Average wind speed in December: 8.1mph

The windiest month (with the highest average wind speed) is March (8.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).

Average humidity in December
South Plainfield, NJ

Average humidity in December - South Plainfield, NJ
  • Average humidity in December: 78%

The months with the highest relative humidity are February, October and December (78%).
The months with the lowest relative humidity are April and August (73%).

Average rainfall in December
South Plainfield, NJ

Average rainfall in December - South Plainfield, NJ
  • Average rainfall in December: 3.19"

The wettest month (with the highest rainfall) is December (3.19").
The driest month (with the least rainfall) is September (1.69").

Average rainfall days in December
South Plainfield, NJ

Average rainfall days in December - South Plainfield, NJ
  • Average rainfall days in December: 11.5 days

The month with the highest number of rainy days is July (16.5 days).
The month with the least rainy days is January (9.5 days).

Average snowfall in December
South Plainfield, NJ

Average snowfall in December - South Plainfield, NJ
  • Average snowfall in December: 1.46"

The month with the highest snowfall is March (3.23").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
South Plainfield, NJ

Average snowfall days in December - South Plainfield, NJ
  • Average snowfall days in December: 4.1 days

The months with the highest number of snowfall days are January and February (7.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
South Plainfield, NJ

Average daylight in December / Average sunshine in December - South Plainfield, NJ
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 4h and 5min

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 36min).

Average sunshine days in December
South Plainfield, NJ

Average sunshine days in December - South Plainfield, NJ
  • Average sunshine days in December: 15.8 days

The month with the most sunshine days is November (18.4 days).
The month with the least sunshine days is June (11.4 days).

Average UV index in December
South Plainfield, NJ

Average UV index in December - South Plainfield, 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
South Plainfield, NJ

Average cloud cover in December - South Plainfield, NJ
  • Average cloud cover in December: 48

The months with the most cloud cover are February, March and December (Cloud cover 48).
The months with the least cloud cover are July and August (Cloud cover 32).

Average visibility in December
South Plainfield, NJ

Average visibility in December - South Plainfield, 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).

South Plainfield, New Jersey, USA

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