In Minnesota, we know a cold day when we see one. The snow crunches and squeaks beneath our feet, smoke and steam plumes drift horizontally, and public spaces appear almost empty (usually).
Climatologically, we know it's cold when high temperatures fail to climb above zero degrees F. This meteorological feat defines us regionally, and sets us apart from other parts of the country, including those that receive far more snow than we do.
For instance, Oswego, New York has had 13 seasons that exceeded Minnesota's all-time seasonal snowfall record of 170.5 inches, but has only had nine days in 92 years with high temperatures that failed to exceed 0 degrees. By comparison, in just 70 years, International Falls has remained at or below zero 828 times! Even stations in far southern Minnesota expect at least a few of these bitterly cold days during a typical winter.
Of course, the severity of Minnesota's winters can vary from one year to the next, and our history has been marked by multi-year episodes of both relentless cold and relative mildness. During exceptionally cold winters, parts of northern Minnesota have had a month's worth of days failing to exceed zero degrees, with up to 20 such days reported as far south as the Iowa border. During much warmer winters, like those of 1877-78 and 2001-02, it is likely that no part of the state recorded a high temperature of zero F or lower. Historically, and depending on the period of record used, northern Minnesota has seen 6-14 of these days per winter, with 3-6 days expected in the Twin Cities and southern Minnesota.
In the past few decades, however, an unprecedented warming of winter has begun affecting these and other cold-weather statistics. Since 1991, Minnesota has lost 30-50% of its days per winter with maximum temperatures at or below zero, equating to losses of 1-3 days in southern Minnesota and up to six days in northern parts of the state. The last time the Twin Cities notched four consecutive days at or below zero was January 1994, and none of the locations mentioned below have recorded a top-10 streak since 1996.
Location (consistent record period) | Greatest total | Proportion winters with none | Average # days (1948-1990) | Average # days (1991-2017) | Change |
|---|---|---|---|---|---|
International Falls (1948-2017) | 30 (1978-79) | 1.4% | 13.8 | 8.7 | -5.1 days per winter (37%) |
Duluth (1875-2017) | 26 (1884-85) | 3.5% | 7.1 | 4.6 | -2.5 days per winter (35%) |
St. Cloud (1922-2017) | 19 (1935-36) | 11.5% | 5.8 | 3.5 | -2.3 days per winter (40%) |
Twin Cities (1874-2017) | 17 (1935-36) | 17.4% | 4.2 | 1.8 | -2.4 days per winter (57%)* |
Rochester (1942-2017) | 14 (1978-79) | 17.1% | 4.5 | 2.6 | -1.9 days per winter (43%) |