December weather forecastHackettstown, NJ
December
Weather in December
December, the first month of the winter in Hackettstown, is still a cold month, with an average temperature varying between 28.4°F (-2°C) and 40.1°F (4.5°C).Temperature
A shift in the average high-temperature occurs in December, reducing from a chilly 49.1°F (9.5°C) in November to a cold 40.1°F (4.5°C). December's nights observe an average temperature of 28.4°F (-2°C).Humidity
February, October and December, with an average relative humidity of 81%, are the most humid months in Hackettstown.Rainfall
In December, the rain falls for 7.1 days. Throughout December, 0.87" (22mm) of precipitation is accumulated. Throughout the year, there are 106.9 rainfall days, and 9.84" (250mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, October through December. In Hackettstown, in December, snow falls for 3.2 days, with typically accumulated 0.71" (18mm) of snow. In Hackettstown, during the entire year, snow falls for 21.7 days and aggregates up to 3.94" (100mm) 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 the month, sunrise is at 7:05 am and sunset at 4:32 pm. On the last day of December, sunrise is at 7:23 am and sunset at 4:41 pm EST.
Sunshine
The average sunshine in December in Hackettstown is 4.7h.UV index
December is the month with the lowest UV index, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: In December, an average UV index of 1 transforms into the following instructions:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Hackettstown, NJ
- Average high temperature in December: 40.1°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (33.8°F).
- Average low temperature in December: 28.4°F
The month with the highest average low temperature is July (63°F).
The coldest month (with the lowest average low temperature) is January (21°F).
Average pressure in December
Hackettstown, 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
Hackettstown, NJ
- Average wind speed in December: 7.3mph
The windiest month (with the highest average wind speed) is March (8mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).
Average humidity in December
Hackettstown, NJ
- Average humidity in December: 81%
The months with the highest relative humidity are February, October and December (81%).
The month with the lowest relative humidity is April (76%).
Average rainfall in December
Hackettstown, NJ
- Average rainfall in December: 0.87"
The wettest month (with the highest rainfall) is July (1.18").
The driest month (with the least rainfall) is September (0.35").
Average rainfall days in December
Hackettstown, NJ
- Average rainfall days in December: 7.1 days
The month with the highest number of rainy days is May (12.2 days).
The month with the least rainy days is January (5.9 days).
Average snowfall in December
Hackettstown, NJ
- Average snowfall in December: 0.71"
The month with the highest snowfall is February (0.98").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Hackettstown, NJ
- Average snowfall days in December: 3.2 days
The month with the highest number of snowfall days is February (6.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Hackettstown, 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 42min
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 30min).
Average sunshine days in December
Hackettstown, NJ
- Average sunshine days in December: 21.3 days
The month with the most sunshine days is January (21.5 days).
The month with the least sunshine days is May (15.4 days).
Average UV index in December
Hackettstown, NJ
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Hackettstown, NJ
- Average cloud cover in December: 49
The month with the most cloud cover is February (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 35).
Average visibility in December
Hackettstown, NJ
- Average visibility in December: 6mi
The months with the highest visibility are January, March, April, November and December (6mi).
The months with the lowest visibility are February, May, June, July, August, September and October (5mi).
