December weather forecastCedar Knolls, NJ
December
Weather in December
The first month of the winter, December, is also an icy month in Cedar Knolls, New Jersey, with an average temperature ranging between max 40.8°F (4.9°C) and min 29.5°F (-1.4°C).Temperature
December brings a minor decrease, with the average high-temperature reducing from a cool 50.5°F (10.3°C) in November to an icy 40.8°F (4.9°C). December nights observe an average temperature dip to a freezing cold 29.5°F (-1.4°C).Humidity
February, October and December, with an average relative humidity of 80%, are the most humid months.Rainfall
In December, the rain falls for 10.9 days. Throughout December, 2.4" (61mm) of precipitation is accumulated. In Cedar Knolls, New Jersey, during the entire year, the rain falls for 157.9 days and collects up to 27.05" (687mm) of precipitation.Snowfall
January through May, November and December are months with snowfall. In Cedar Knolls, in December, snow falls for 3.8 days, with typically accumulated 1.06" (27mm) of snow. In Cedar Knolls, New Jersey, during the entire year, snow falls for 24 days and aggregates up to 9.72" (247mm) 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 December, sunrise is at 7:03 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 Cedar Knolls, the average sunshine in December is 4.8h.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 reading of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the average person.Note: A maximum daily UV index of 2 during December morphs into the following directions:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Cedar Knolls, NJ
- Average high temperature in December: 40.8°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (34.9°F).
- Average low temperature in December: 29.5°F
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in December
Cedar Knolls, 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
Cedar Knolls, NJ
- Average wind speed in December: 7.6mph
The windiest month (with the highest average wind speed) is March (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).
Average humidity in December
Cedar Knolls, NJ
- Average humidity in December: 80%
The months with the highest relative humidity are February, October and December (80%).
The month with the lowest relative humidity is April (74%).
Average rainfall in December
Cedar Knolls, NJ
- Average rainfall in December: 2.4"
The wettest month (with the highest rainfall) is July (3.19").
The driest months (with the least rainfall) are January, February and September (1.57").
Average rainfall days in December
Cedar Knolls, NJ
- Average rainfall days in December: 10.9 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is January (8.3 days).
Average snowfall in December
Cedar Knolls, NJ
- Average snowfall in December: 1.06"
The month with the highest snowfall is March (3.7").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Cedar Knolls, NJ
- Average snowfall days in December: 3.8 days
The month with the highest number of snowfall days is February (6.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Cedar Knolls, NJ
- Average daylight in December: 9h and 18min
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 48min
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).
Average sunshine days in December
Cedar Knolls, NJ
- Average sunshine days in December: 16.8 days
The month with the most sunshine days is November (19 days).
The month with the least sunshine days is July (10.9 days).
Average UV index in December
Cedar Knolls, 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
Cedar Knolls, NJ
- Average cloud cover in December: 49
The months with the most cloud cover are February, March and December (Cloud cover 49).
The months with the least cloud cover are July and August (Cloud cover 34).
Average visibility in December
Cedar Knolls, NJ
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, July, August, October, November and December (6mi).
The months with the lowest visibility are May, June and September (5mi).
