Researchers analyzed meteorological data from nine Upper Midwest states from 1979–2021, tracking trends in extreme heat and cold over every 4-kilometer square of that territory. They found striking regional differences in the extremes. Many parts of the Upper Midwest experienced significant upticks in the number of extreme heat days over the 40 years—an increasing trend—while others saw a rise in extreme cold events. Some communities experienced more of both extremes. Others appeared to be more resistant to changes in extreme heat or cold.
