December weather forecastMorristown, NJ
December
Weather in December
Engulfed in the spirit of winter, December can be harsh for a non-winter admirer. A high chance of snowfall and a marked drop in temperature is common, plummeting to an average low of 29.7°F (-1.3°C). Despite being the month with the least daylight hours, numerous lights decorate the cityscape creating a vivid spectacle. Warm clothing, fireplaces, and hot cocoa constitute an integral part of daily lives. Morristown in December is a winter wonderland, sparkling under the holiday lights.Temperature
In Morristown, the average high-temperature in December decreases from a cool 50.5°F (10.3°C) in November to a wintry 40.8°F (4.9°C). Morristown's nights in December cool down to an average low-temperature of 29.7°F (-1.3°C).Humidity
The months with the highest humidity in Morristown are February and December, with an average relative humidity of 80%.Rainfall
In December, in Morristown, the rain falls for 11.6 days. Throughout December, 3.03" (77mm) of precipitation is accumulated. In Morristown, during the entire year, the rain falls for 164.2 days and collects up to 30.67" (779mm) of precipitation.Snowfall
Months with snowfall in Morristown are January through May, October through December. In Morristown, in December, snow falls for 4 days, with typically accumulated 1.61" (41mm) of snow. Throughout the year, in Morristown, there are 26 snowfall days, and 11.61" (295mm) of snow is accumulated.Daylight
With an average of 9h and 18min of daylight, December has the shortest days of the year in Morristown, New Jersey.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
In Morristown, 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 estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.Note: During December, 2 as the daily maximum UV index converts into the following advice:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Morristown, 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 (35.1°F).
- Average low temperature in December: 29.7°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
Morristown, 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
Morristown, 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
Morristown, NJ
- Average humidity in December: 80%
The months with the highest relative humidity are February and December (80%).
The months with the lowest relative humidity are April and August (74%).
Average rainfall in December
Morristown, NJ
- Average rainfall in December: 3.03"
The wettest month (with the highest rainfall) is July (3.27").
The driest month (with the least rainfall) is September (1.69").
Average rainfall days in December
Morristown, NJ
- Average rainfall days in December: 11.6 days
The month with the highest number of rainy days is July (17.4 days).
The month with the least rainy days is January (8.8 days).
Average snowfall in December
Morristown, NJ
- Average snowfall in December: 1.61"
The month with the highest snowfall is March (3.5").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Morristown, NJ
- Average snowfall days in December: 4 days
The month with the highest number of snowfall days is January (7.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Morristown, 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
Morristown, NJ
- Average sunshine days in December: 15.6 days
The month with the most sunshine days is November (18.3 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in December
Morristown, 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
Morristown, NJ
- Average cloud cover in December: 48
The months with the most cloud cover are February and March (Cloud cover 49).
The months with the least cloud cover are July and August (Cloud cover 34).
Average visibility in December
Morristown, 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).
