December weather forecast and climate
Griggstown, NJ

The first month of the winter, December, is also a frosty month in Griggstown, New Jersey, with average temperature fluctuating between 31.1°F (-0.5°C) and 43°F (6.1°C).

Temperature

In December, the average high-temperature slightly decreases, from a fresh 51.8°F (11°C) in November, to a chilly 43°F (6.1°C). In December, the average low-temperature is 31.1°F (-0.5°C).

Humidity

The average relative humidity in December is 78%.

Rainfall

In Griggstown, New Jersey, during December, the rain falls for 8.2 days and regularly aggregates up to 1.26" (32mm) of precipitation. Throughout the year, there are 119.3 rainfall days, and 12.72" (323mm) of precipitation is accumulated.

Snowfall

January through May, November and December are months with snowfall in Griggstown. In Griggstown, in December, snow falls for 2.7 days, with typically accumulated 0.75" (19mm) of snow. In Griggstown, during the entire year, snow falls for 16.4 days, and aggregates up to 4.41" (112mm) of snow.

Daylight

With an average of 9.3h of daylight, December has the shortest days of the year.

Sunshine

The average sunshine in Griggstown is 5h.

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 of 2, and less, symbolizes a low health risk from unprotected exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 2 transform into the following instructions:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. 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. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the temperature in December in Griggstown?

In December, the average high-temperature is 43°F (6.1°C), and the average low-temperature is 31.1°F (-0.5°C).

What is the average humidity in December in Griggstown?

The average relative humidity in December in Griggstown, New Jersey, is 78%.

How many days does it rain in December in Griggstown?

In December, in Griggstown, New Jersey, the rain falls for 8.2 days. Throughout December, 1.26" (32mm) of precipitation is accumulated.

How many days does it snow in December in Griggstown?

In Griggstown, in December, during 2.7 snowfall days, 0.75" (19mm) of snow is typically accumulated.

What is the month with the shortest days in Griggstown?

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

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

The average length of the day in December in Griggstown is 9.3h.

How long on average sun shines in December in Griggstown?

In December, the average sunshine in Griggstown is 5h.

When is the lowest UV index in Griggstown?

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

What is the UV index reading in December in Griggstown?

In December, the average daily maximum UV index in Griggstown, New Jersey, is 2. A UV Index value of 2, and less, symbolizes a low health threat from the exposure to the Sun's UV rays.
Average temperature in December - Griggstown, NJ
  • Average high temperature in December: 6.1°C

The warmest month (with the highest average high temperature) is July (29.3°C).
The month with the lowest average high temperature is January (2.7°C).

  • Average low temperature in December: -0.5°C

The month with the highest average low temperature is July (19.4°C).
The coldest month (with the lowest average low temperature) is January (-4.3°C).

Average pressure in December - Griggstown, NJ
  • Average pressure in December: 1018.7mbar

The month with the highest atmospheric pressure is November (1019.7mbar).
The month with the lowest atmospheric pressure is June (1013.7mbar).

Average wind speed in December - Griggstown, NJ
  • Average wind speed in December: 12.6km/h

The windiest month (with the highest average wind speed) is March (14.1km/h).
The calmest month (with the lowest average wind speed) is August (8.7km/h).

Average humidity in December - Griggstown, NJ
  • Average humidity in December: 78%

The month with the highest relative humidity is October (79%).
The month with the lowest relative humidity is April (73%).

Average rainfall in December - Griggstown, NJ
  • Average rainfall in December: 32mm

The wettest month (with the highest rainfall) is July (43mm).
The driest month (with the least rainfall) is September (17mm).

Average rainfall days in December - Griggstown, NJ
  • Average rainfall days in December: 8.2 days

The month with the highest number of rainy days is July (13.9 days).
The month with the least rainy days is January (6.1 days).

Average snowfall in December - Griggstown, NJ
  • Average snowfall in December: 19mm

The month with the highest snowfall is March (36mm).
Months with the least snowfall are June, July, August, September and October (0mm).

Average snowfall days in December - Griggstown, NJ
  • Average snowfall days in December: 2.7 days

The month with the highest number of snowfall days is January (4.6 days).
Months with the least snowfall days are June, July, August, September and October (0 days).

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

The month with the longest days is June (Average daylight: 15h).
The month with the shortest days is December (Average daylight: 9.3h).

  • Average sunshine in December: 5h

The month with the most sunshine is July (Average sunshine: 10.5h).
The month with the least sunshine is February (Average sunshine: 4.8h).

Average sunshine days in December - Griggstown, NJ
  • Average sunshine days in December: 20.5 days

The month with the most sunshine days is January (21.8 days).
The month with the least sunshine days is July (13.3 days).

Average UV index in December - Griggstown, 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).

Average cloud cover in December - Griggstown, NJ
  • Average cloud cover in December: 47

Months with the most cloud cover are February, March and December (Cloud cover 47).
Months with the least cloud cover are July and August (Cloud cover 33).

Average visibility in December - Griggstown, NJ
  • Average visibility in December: 9km

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).