Surprise Winter Storm Drops 17 Inches of Snow in Wyoming Just Days After 100-degree Weather

The change in weather set the record for the earliest freeze.

Snow in Colorado
University of Colorado Boulder students play in the snow during an early-season winter storm on September 9, 2020 in Boulder, Colorado. . Photo: Michael Ciaglo/Getty Images

The Great Plains and the Rocky Mountains experienced an early dose of winter weather this week as 17 inches of snow covered parts of the country.

The quick change in weather, from summer to winter, came seemingly without warning as Rapid City, S.D. set a U.S. record for the fastest switch between 100-degrees, according to NBC News. On Sept. 5, the city reported a temperature of 102 degrees Fahrenheit, an all-time record high for September weather. Two days later, an inch of snow fell and the city set a new record for the earliest first freeze.

The two-day difference broke the record for the shortest amount of time between those two weather patterns (the previous record was three days, set by Ardmore, South Dakota in September 1929).

The top snowfall this week was set by Casper, Wyoming — which recorded a total of 17 inches of snowfall. Red Lodge, Montana reported 15.5 inches of snow and Terry Peak, South Dakota reported 15 inches.

More than 5 million people in the Northern and Central Rockies were under winter weather alerts on Wednesday morning as snow continued to fall. Parts of Colorado and New Mexico reported their earliest snowfall on record. Citizens of Denver woke up Wednesday to a few inches of snowfall after summertime weather during Labor Day weekend.

The snow is unlikely to linger, with temperatures back in the 70s expected for much of the area by this weekend. But this past week may be an indicator of what to expect for the rest of the month. The Climate Prediction Center (CPC) predicts that the north-central Plains can expect a cooler-than-normal month and the south-central Plains can expect a September that is wetter than normal, due to hurricane patterns. The west can expect warmer and drier-than-normal conditions through the end of the month.

Cailey Rizzo is a contributing writer for Travel + Leisure, currently based in Brooklyn. When in a new city, she's usually out to discover under-the-radar art, culture, and secondhand stores. No matter her location, you can find her on Twitter, on Instagram or at

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