December weather forecastMahwah, NJ
December
Weather in December
As Mahwah steps into December, it gets enveloped in the encompassing cold of the winter season. With falling temperatures comes an increased likelihood of snowfall with an approximate accumulation of 1.81" (46mm) across 5.1 days. Clear, cold, and crisp days define Mahwah's mid-winter weather, wrapping up the year on a frosty yet beautiful note.Temperature
Mahwah's December weather features a mild decline in high-temperatures, reducing from a cool 50°F (10°C) in November to a wintry 40.1°F (4.5°C). Mahwah records an average nighttime low-temperature of 29.1°F (-1.6°C) throughout December.Humidity
The months with the highest humidity are February and December, with an average relative humidity of 79%.Rainfall
The month with the most rainfall is December, when the rain falls for 10.8 days and typically aggregates up to 2.68" (68mm) of precipitation.Snowfall
Months with snowfall in Mahwah are January through May, October through December. In Mahwah, in December, during 5.1 snowfall days, 1.81" (46mm) of snow is typically accumulated. In Mahwah, during the entire year, snow falls for 28.5 days and aggregates up to 10.98" (279mm) 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 7:02 am and sunset at 4:28 pm. On the last day of December, in Mahwah, sunrise is at 7:21 am and sunset at 4:38 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 value of 2, and less, symbolizes a low health risk from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 2 in December converts into the following recommendations:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Mahwah, NJ
- Average high temperature in December: 40.1°F
The warmest month (with the highest average high temperature) is July (84.2°F).
The month with the lowest average high temperature is January (34.3°F).
- Average low temperature in December: 29.1°F
The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (21.7°F).
Average pressure in December
Mahwah, NJ
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is November (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Mahwah, NJ
- Average wind speed in December: 7.1mph
The windiest month (with the highest average wind speed) is March (7.7mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in December
Mahwah, NJ
- Average humidity in December: 79%
The months with the highest relative humidity are February and December (79%).
The month with the lowest relative humidity is April (72%).
Average rainfall in December
Mahwah, NJ
- Average rainfall in December: 2.68"
The wettest month (with the highest rainfall) is December (2.68").
The driest month (with the least rainfall) is September (1.34").
Average rainfall days in December
Mahwah, NJ
- Average rainfall days in December: 10.8 days
The month with the highest number of rainy days is July (16.6 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in December
Mahwah, NJ
- Average snowfall in December: 1.81"
The month with the highest snowfall is February (2.91").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Mahwah, NJ
- Average snowfall days in December: 5.1 days
The month with the highest number of snowfall days is February (7.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Mahwah, 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 24min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).
Average sunshine days in December
Mahwah, NJ
- Average sunshine days in December: 15.7 days
The month with the most sunshine days is November (18.8 days).
The month with the least sunshine days is June (11.8 days).
Average UV index in December
Mahwah, 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
Mahwah, NJ
- Average cloud cover in December: 48
The months with the most cloud cover are February and March (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 33).
Average visibility in December
Mahwah, NJ
- Average visibility in December: 6mi
The months with the highest visibility are January, March, April, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are February and May (5mi).
