The mercury also dropped into negative territory in Milwaukee, St. Louis and Chicago, which set a record for the date at minus 16. Wind chills across the region were 40 below and colder. Records also fell in Oklahoma, Texas and Indiana.
Authorities in Indiana and Kentucky -#8212; where temperatures dropped into the single digits and below, with wind chills in the minus 20s and worse -#8212; warned people not to leave their homes at all unless they needed to go someplace safer.
Utility crews in Indiana worked to restore power to more than 40,000 customers affected by the weekend storm and cautioned that some people could be in the cold and dark for days.
Several deaths were blamed on the snow, ice and cold since Saturday, including the death of a 1-year-old boy who was in a car that went out of control and collided with a snowplow Monday in Missouri.
In the eastern United States, temperatures in the 40s and 50s Monday helped melt piles of snow from a storm last week, raising the risk that roads would freeze over as the cold air moved in Monday night, said Bob Oravec from the Weather Prediction Center in College Park, Md. The snap was set to be dramatic; Springfield, Mass., enjoyed 56 degrees Monday morning but faced an overnight low of 6.
More than 3,700 flights were canceled by late Monday afternoon, following a weekend of travel disruption across the nation. Airline officials said de-icing fluid was freezing, fuel was pumping sluggishly, and ramp workers were having difficulty loading and unloading luggage.
JetBlue Airways stopped all scheduled flights to and from New York and Boston on Monday. Southwest ground to a halt in Chicago earlier in the day, but by the evening, flights resumed in "a trickle," a spokesman said.
Locally, San Francisco International Airport had 24 cancelled departures and 32 cancelled arrivals on Monday by 5 p.m. At Oakland International Airport, five departing flights and eight arrivals had been cancelled.
"Airports back east are doing the best they can but it's a total mess," said Scott Wintner, spokesman for the Oakland airport. "Planes are super full because people are headed home, back to school after the holidays.
Delays of up to two hours were not uncommon Monday at Bay Area airports. Wintner suggested that people check the status of their flight before heading to the airport.