December weather forecastPrinceton, NJ
December
Weather in December
December manifests the return of winter to Princeton, complete with shorter days and frigid temperatures. The month also sees an increase in snowfall, setting the stage for the white Christmas just in line with the festive spirit. December's relatively stable weather, characterized by snow and cold, signals the impending full-fledged winter. Compared to November, December fosters chilled temperatures, increased snowfalls, and the shortest daylight of the year.Temperature
With the onset of December, Princeton experiences a modest temperature adjustment, with the average high-temperature gently receding from a fresh 51.8°F (11°C) in November to a chilly 43°F (6.1°C). Princeton experiences a steady low-temperature of 31.1°F (-0.5°C) throughout December.Humidity
In Princeton, the average relative humidity in December is 78%.Rainfall
In Princeton, 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 December, it is snowing for 2.7 days. Throughout December, 0.75" (19mm) of snow is accumulated. In Princeton, during the entire year, snow falls for 16.4 days and aggregates up to 4.41" (112mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 24min of daylight.On the first day of December, sunrise is at 7:02 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:42 pm EST.
Sunshine
The average sunshine in December is 5h.UV index
The months with the lowest UV index in Princeton, New Jersey, 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 ordinary individuals.Note: In December, the UV index of 2 transforms into the following advice:
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 best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance. Take heed! Reflection from the snow can almost amplify the Sun's UV radiation by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Princeton, NJ
- Average high temperature in December: 43°F
The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (36.9°F).
- Average low temperature in December: 31.1°F
The month with the highest average low temperature is July (66.9°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in December
Princeton, 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
Princeton, NJ
- Average wind speed in December: 7.8mph
The windiest month (with the highest average wind speed) is March (8.8mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).
Average humidity in December
Princeton, 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
Princeton, NJ
- Average rainfall in December: 1.26"
The wettest month (with the highest rainfall) is July (1.69").
The driest month (with the least rainfall) is September (0.67").
Average rainfall days in December
Princeton, 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
Princeton, NJ
- Average snowfall in December: 0.75"
The month with the highest snowfall is March (1.42").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Princeton, NJ
- Average snowfall days in December: 2.7 days
The month with the highest number of snowfall days is January (4.6 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
Princeton, NJ
- Average daylight in December: 9h and 24min
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 24min).
- Average sunshine in December: 5h and 0min
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 48min).
Average sunshine days in December
Princeton, 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
Princeton, 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
Princeton, NJ
- Average cloud cover in December: 47
The months with the most cloud cover are February, March and December (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 33).
Average visibility in December
Princeton, 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).
