Temperatures plunged to as low as 28 below zero Monday as another wave of arctic air surged across the Great Lakes.
A number of schools opened late in eastern upstate New York because several inches of snow had fallen during the night.
"It is cold enough that the salt doesn't do quite as good a job," National Weather Service meteorologist Ken LaPenta said in Albany, where morning temperatures were in the single digits.
"It was around 1 or 2 below, and salt has no effect on that," said Ohio Highway Patrol Lt. Ron Kuszmaul in Delaware, Ohio. "It just remained glazed."
New York state had no record low temperatures but Watertown, at the eastern end of Lake Ontario, hit 28 below zero, and Massena fell to 16 below.
The morning low was 24 below at Eagle River, Wis., near Michigan's Upper Peninsula.
"It's very bitter, bitter cold," Becky Kulick said at Eagle River. "But we're used to it. You've got to expect it up here in January."
The mercury also fell below zero in Ohio, where Lancaster hit 17 below and Mansfield had a record 9 below.
Hundreds of Ohio schools closed or delayed opening because of the cold and slick streets.
At the opposite extreme, southern California has had a heat wave with temperatures nudging 90 degrees. Surfers and sun worshippers flocked to beaches during the weekend.
Newport Beach warmed to a record high of 83 on Sunday and Yorba Linda peaked at a record 88.