In West Yellowstone, Mont., a hamlet on the doorstep of Yellowstone National Park and a frequent icebox, the mercury plummeted to 45 below zero, shattering the old record for Dec. 7 of 39 below set in 1927.
"I played taxi service this morning to a lot of my employees because their cars wouldn't start," said Gayle Archer, a manager at one of the town's motels, who watched other residents ski to work on unplowed streets.
In Denver, the coroner was trying to determine if the death of a homeless man was caused by temperatures that dropped to 11 below.
Schools in the Colorado Springs area were closed and many others statewide opened late.
The cold extended south to the Texas Panhandle, where Lubbock had a record low of 6 degrees. At Dallas-Fort Worth Airport, officials said freezing rain was expected to force the cancellation of hundreds of flights.
"It's just pretty cold," said Charles Bowers, a rancher and cotton farmer near Pampa, a town 145 miles south of Lubbock where it was 10 degrees at noon.
Temperatures read like ice hockey scores in northeastern New Mexico — zero at Las Vegas and 1 at Raton. "I'm sitting here in my office and it's freezing and we've got the heat on full blast," said Bill Cox, owner of the Hillcrest Restaurant in Las Vegas.
The cold follows a blizzard that blasted much of the Plains on Nov. 27-28, shutting down major highways across a half-dozen states.
Some 3,600 rural customers in South Dakota were still without electricity more than a week later, said Tom Dravland, state public safety secretary. Lows across the eastern part of the state dipped to as much as 20 below.
Outreach workers in Denver were encouraging homeless people to head to shelters, which were taking in extra people, said Deborah Ortega, executive director of the Denver Commission to End Homelessness. The Salvation Army's search and rescue team was out all night.
Brad Meuli, president of the Denver Rescue Mission, said about 300 people — about 100 more than they are normally allowed to take in — squeezed into a downtown shelter Tuesday.
"We're not turning anyone away. We may just give them a blanket and have them lean up against a wall," he said.
Inside a 115-year-old cabin on Colorado's Hohnholz Ranch near the Wyoming line, Bob and Phyllis Hohnholz, both in their 80s, said they had their fireplace blazing. It was 37 below at the ranch overnight Tuesday — the coldest spot in the state.
Elsewhere Wednesday, the weather service said record lows for the date included 28 below zero at Drummond, Mont., 25 below at Laramie, Wyo., 17 below at Alliance, Neb.; 19 below at Cedar Rapids, Iowa; and 3 below at Lincoln, Ill.