December weather forecastIselin, NJ
December
Weather in December
December, the first month of the winter in Iselin, is also a wintry month, with temperature in the range of an average low of 32.9°F (0.5°C) and an average high of 42.4°F (5.8°C).Temperature
December heralds a minor drop in average high-temperature, sliding from November's fresh 51.3°F (10.7°C) to an icy 42.4°F (5.8°C). December brings an average low-temperature of 32.9°F (0.5°C) to Iselin.Humidity
The average relative humidity in December is 76%.Rainfall
In December, in Iselin, the rain falls for 7.3 days. Throughout December, 0.83" (21mm) of precipitation is accumulated. Throughout the year, in Iselin, there are 110.2 rainfall days, and 8.9" (226mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, November and December. In Iselin, during December, snow falls for 2.8 days and regularly aggregates up to 0.24" (6mm) of snow. In Iselin, during the entire year, snow falls for 14.5 days and aggregates up to 1.85" (47mm) of snow.Daylight
With an average of 9h and 18min of daylight, December has the shortest days of the year.On the first day of December in Iselin, sunrise is at 7:02 am and sunset at 4:30 pm. On the last day of the month, sunrise is at 7:20 am and sunset at 4:40 pm EST.
Sunshine
The average sunshine in December in Iselin, New Jersey, is 4.9h.UV index
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: The UV index of 2 in December translates into these instructions:
Children necessitate constant protection from sunlight, unlike the majority, who can remain under the sun for about an hour without burning. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Stay alert! Snow's reflective properties can almost double the UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Iselin, NJ
- Average high temperature in December: 42.4°F
The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is January (36.5°F).
- Average low temperature in December: 32.9°F
The month with the highest average low temperature is July (68.9°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).
Average pressure in December
Iselin, 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
Iselin, NJ
- Average wind speed in December: 8.9mph
The windiest months (with the highest average wind speed) are January and March (9.6mph).
The calmest month (with the lowest average wind speed) is July (6.3mph).
Average humidity in December
Iselin, NJ
- Average humidity in December: 76%
The month with the highest relative humidity is February (77%).
The month with the lowest relative humidity is August (72%).
Average rainfall in December
Iselin, NJ
- Average rainfall in December: 0.83"
The wettest month (with the highest rainfall) is July (1.22").
The driest month (with the least rainfall) is September (0.39").
Average rainfall days in December
Iselin, NJ
- Average rainfall days in December: 7.3 days
The month with the highest number of rainy days is July (12.7 days).
The month with the least rainy days is January (4.9 days).
Average snowfall in December
Iselin, NJ
- Average snowfall in December: 0.24"
The month with the highest snowfall is March (0.83").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Iselin, NJ
- Average snowfall days in December: 2.8 days
The month with the highest number of snowfall days is February (4.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Iselin, NJ
- Average daylight in December: 9h and 18min
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 18min).
- Average sunshine in December: 4h and 54min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in December
Iselin, NJ
- Average sunshine days in December: 21.3 days
The month with the most sunshine days is January (22.6 days).
The month with the least sunshine days is July (14.8 days).
Average UV index in December
Iselin, 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
Iselin, 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 30).
Average visibility in December
Iselin, NJ
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
