Coldest Temperature in Contiguous United States

In January 1954, at the 4 K's Mine near Rogers Pass, Montana, four miners—brothers Albert and Harry Hleinschmidt, their nephew Harrison Mercer (H.M.) Kleinschmidt, and Leroy Keil of Elliston—endured a brutal winter storm as snow depth climbed above five feet between January 13th and 20th, with at least six inches falling each day and 28.5 inches on the 14th. Around 2 a.m., Kleinschmidt checked his personal thermometer outside the cabin and found a reading of -68ºF, then made his way through six-foot snow tunnels to the instrument shelter, where the official thermometer had exceeded its measuring capacity of -65ºF and its indicator had receded into the reservoir bulb. Because the miners lived simply without electricity or a telephone, the observation remained unknown for weeks until February 3rd, when State Climatologist Richard Dightman of the U.S. Weather Bureau in Helena reviewed the mailed monthly forms and recognized that the reading would surpass the previous United States record of -66ºF set at West Yellowstone on February 9th, 1933. After testing in Washington D.C., the thermometers were found to perform as Kleinschmidt had reported, and on March 16th the January 20th, 1954 measurement was officially adjusted to -70F and accepted as the new all-time record low for the United States, a mark later surpassed in Alaska on January 23, 1971, but still the coldest temperature ever recorded in Montana and in the contiguous United States.

Montana · United States