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Weather Wise: 70 below zero

Rogers Pass marker of 70 degrees below zero
Posted at 6:32 PM, Jan 18, 2021
and last updated 2021-01-19 10:29:14-05

HELENA — Montana is king when it comes to temperature records. We've got the all-time temperature range from a high of 117 degrees at Glendive and Medicine Lake, to a low of 70 degrees below zero at Rogers Pass. That's a 187-degree difference, and is the widest range of any of the 50 states.

The greatest temperature change in 24 hours happened in Loma on January 15, 1972 - the temperature went from -54 to 49 degrees, a difference of 103 degrees, setting a still-standing world record.

The biggest 12-hour change happened on December 14, 1924 in Fairfield, when the the temperature dropped from 63 degrees to -21 degrees, a change of 84 degrees, a still-standing U.S. record.

The temperature at the Great Falls International Airport on January 11, 1980, went from -32 degrees to 15 degrees in just seven minutes when Chinook winds blew through; the 47-degree change in just seven minutes marks the U.S. record for the most rapid temperature change.

The most amazing temperature record is from Rogers Pass in Lewis & Clark County, where the temperature once hit 70 below - and likely even a little colder.

Rick and Susie Graetz, writing for the University of Montana, explained:

It happened in a small, high mountain valley with 5 and a half feet of snow on the ground – 58 inches of which had fallen recently. The minus 70 degree reading was not representative of the more densely populated areas of the state. That same night a low of minus 31 degrees occurred in Butte, minus 43 degrees in Havre, minus 34 degrees in Billings, minus 37 degrees in Great Falls, minus 36 degrees in Helena and minus 14 degrees in Missoula.
The facts that the two thermometers behaved in the laboratory exactly as described by the observer, that temperatures of minus 57 degrees and minus 59 degrees were recorded in the same general area and that the observer was not aware that he was recording a record temperature were sufficient evidence to adopt the minus 70 degree record.