Snow covering the ground contributed to the frigid temperature readings Monday morning.
In case you didn't notice, temperatures across New Jersey took another nose dive overnight Sunday into early Monday morning, thanks to the lingering Arctic air and the snow from the weekend storm.
The mercury plunged below zero in parts of central and southern New Jersey -- without the wind chill factored in -- according to temperature data from the National Weather Service and the New Jersey Weather & Climate Network at Rutgers University.
The lowest reading reported Monday morning was 8 degrees below zero in Berkeley Township in Ocean County, followed by 6 below zero in Toms River in Ocean, and 4 below zero in Millville in Cumberland County.
A few weather observation stations around the state hit 2 below zero: Howell in Monmouth County, Hopewell in Mercer County and the Piney Hollow section of Newfield Borough in Gloucester County.
Updated snow totals from weekend storm
The snow on the ground from Saturday's winter storm played a role in the frigid temperatures Monday morning, said Lance Franck, a meteorologist at the National Weather Service's forecast office in Mount Holly.
"We had the ideal radiational (nighttime) cooling and the fresh deep snow pack, which contributed several degrees to those numbers," Franck said. "Without the snow pack, it wouldn't have been that cold."
New Jersey State Climatologist David Robinson, who teaches at Rutgers University and oversees the New Jersey Weather & Climate Network, agrees the fresh snow cover was a factor in the frigid temperature readings.
Good evidence, he said, is the fact it was colder Monday morning in Ocean County than it was in Sussex County. On calm, clear mornings, like the one that greeted New Jerseyans when they woke up on Monday, the Sussex town of Walpack often has the coldest temperature readings across the state, Robinson said.
Early Monday, the low temperature in Walpack was 1 degree above zero -- still very frigid, but not as cold as the 8 degrees below zero in Berkeley Township. In Saturday's storm, Berkeley got hit with more than 8 inches of snow, and most sections of Sussex County received only a trace to 2 inches.
"The fresh snow helps to insulate the atmosphere from the milder ground under the snow," Robinson said. "It also serves as a sponge of sorts, drying out the overlying air, which allows it to cool more efficiently."
For New Jerseyans who are tired of bundling up, a bit of relief is on the way later this week. After coping with the threat of light snow showers and freezing rain in the state's northwestern region Tuesday afternoon into Tuesday night, temperatures will begin to warm up on Wednesday, Thursday and Friday.
Temperatures on those days are forecast to climb into the upper 40s to low 50s in North Jersey and the low 50s to upper 50s in South Jersey.
Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com. Follow him on Twitter @LensReality or like him on Facebook. Find NJ.com on Facebook.