December weather forecast
Westfield, NJ

December

Weather in December

December, the first month of the winter in Westfield, is also a wintry month, with temperature in the range of an average high of 5.7°C and an average low of -0.5°C.

Temperature

The arrival of December is marked by a minor reduction in average high-temperature, sliding from a fresh 10.6°C in November to a cold 5.7°C. Westfield, during the month of December, experiences an average low-temperature of -0.5°C.

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 81mm of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In December, it is snowing for 4.1 days. Throughout December, 37mm of snow is accumulated. Throughout the year, there are 25.4 snowfall days, and 262mm 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 December, sunrise is at 7:02 am and sunset at 4:30 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:40 pm EST.

Sunshine

In December, the average sunshine 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 reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation for average individuals.
Note: The UV index of 2 in December translates into these instructions:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. To protect against the Sun's most potent rays, avoid direct exposure around midday. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.

Frequently asked questions

How cold does it get in December?
In December, in Westfield, the average high-temperature is 5.7°C, and the average low-temperature is -0.5°C. In August, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which combines air temperature and relative humidity, is calculated to be 31°C.
What is the most humid month in Westfield?
February, October and December, with an average relative humidity of 78%, are most humid months.
What is the average humidity in December?
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 81mm of precipitation.
How many days does it rain in December?
In December, the rain falls for 11.5 days. Throughout December, 81mm of precipitation is accumulated.
How many days does it snow in December?
In Westfield, in December, snow falls for 4.1 days, with typically accumulated 37mm of snow.
What is the month with the shortest days?
The month with the shortest days in Westfield is December, with an average of 9h and 18min of daylight.
How many hours of daylight does Westfield have in December?
In Westfield, the average day length in December is 9h and 19min.
What time are sunrise and sunset in December in Westfield?
On the first day of December, sunrise is at 7:02 am and sunset at 4:30 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 is 4.9h.
When is 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?
The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from unsafe exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility
Average temperature in December - Westfield, NJ
Average temperature in December
Westfield, NJ
  • Average high temperature in December: 5.7°C

The warmest month (with the highest average high temperature) is July (29°C).
The month with the lowest average high temperature is January (2.2°C).

  • Average low temperature in December: -0.5°C

The month with the highest average low temperature is July (19.7°C).
The coldest month (with the lowest average low temperature) is January (-4.5°C).

Average pressure in December - Westfield, NJ
Average pressure in December
Westfield, NJ
  • Average pressure in December: 1018.6mbar

The month with the highest atmospheric pressure is November (1019.6mbar).
The month with the lowest atmospheric pressure is June (1013.7mbar).

Average wind speed in December - Westfield, NJ
Average wind speed in December
Westfield, NJ
  • Average wind speed in December: 13.1km/h

The windiest month (with the highest average wind speed) is March (14.4km/h).
The calmest months (with the lowest average wind speed) are July and August (9.2km/h).

Average humidity in December - Westfield, NJ
Average humidity in December
Westfield, 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 - Westfield, NJ
Average rainfall in December
Westfield, NJ
  • Average rainfall in December: 81mm

The wettest month (with the highest rainfall) is December (81mm).
The driest month (with the least rainfall) is September (43mm).

Average rainfall days in December - Westfield, NJ
Average rainfall days in December
Westfield, 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 - Westfield, NJ
Average snowfall in December
Westfield, NJ
  • Average snowfall in December: 37mm

The month with the highest snowfall is March (82mm).
The months with the least snowfall are June, July, August and September (0mm).

Average snowfall days in December - Westfield, NJ
Average snowfall days in December
Westfield, 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 - Westfield, NJ
Average daylight in December /
Average sunshine in December
Westfield, 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 - Westfield, NJ
Average sunshine days in December
Westfield, 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 - Westfield, NJ
Average UV index in December
Westfield, 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 - Westfield, NJ
Average cloud cover in December
Westfield, 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 - Westfield, NJ
Average visibility in December
Westfield, NJ
  • Average visibility in December: 9km

The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (9km).
The month with the lowest visibility is May (8km).

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