December weather forecastMorris Plains, NJ
December
Weather in December
The first month of the winter, December, is still a cold month in Morris Plains, New Jersey, with an average temperature varying between 29.5°F (-1.4°C) and 40.8°F (4.9°C).Temperature
With the onset of December, Morris Plains's average high-temperature adjusts, receding from November's cool 50.5°F (10.3°C) to a cold 40.8°F (4.9°C). During December, Morris Plains observes a consistent average nighttime temperature of 29.5°F (-1.4°C).Humidity
The months with the highest humidity in Morris Plains are February, October and December, with an average relative humidity of 80%.Rainfall
In Morris Plains, in December, during 10.9 rainfall days, 2.4" (61mm) of precipitation is typically accumulated. Throughout the year, there are 157.9 rainfall days, and 27.05" (687mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, November and December. In Morris Plains, in December, snow falls for 3.8 days, with typically accumulated 1.06" (27mm) of snow. Throughout the year, there are 24 snowfall days, and 9.72" (247mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 18min of daylight.On the first day of the month, sunrise is at 7:03 am and sunset at 4:30 pm. On the last day of December, sunrise is at 7:22 am and sunset at 4:40 pm EST.
Sunshine
The average sunshine in December is 4.8h.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 ordinary individuals.Note: An average maximum UV index of 2 in December leads to these recommendations:
Children must always have sun protection, unlike most people, who can tolerate up to an hour in the sun without any burns. For skin protection, it's recommended to minimize Sun exposure during its peak hours around midday. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key. 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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
Morris Plains, 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).
