Heat in the Heartland

The Union of Concerned Scientists reports that cities in the US Midwest have experienced an increase in heat waves and dangerously hot, humid days over the last six decades. Analysis of ten cities, including St. Louis, Chicago, Detroit, and the Twin Cities, shows a rise in the frequency of heat waves and a corresponding loss of cool, comfortable summer days. These trends increase the risk of hyperthermia and dehydration, particularly for vulnerable populations such as the elderly, children, and those with pre-existing medical conditions. The document advocates for city-level preparedness and the reduction of fossil fuel emissions to mitigate these health risks.

• Analysis of ten Midwest cities indicates that hot summer weather and heat waves have become more frequent over the last 60 years, while the number of cool, comfortable summer days has decreased.
• Specific city data shows significant increases in extreme heat: St. Louis has nearly tripled its number of heat waves (from three to almost nine) and more than doubled its hot, humid days (from six to more than 15). Chicago has gained one heat wave per average summer and six dangerously hot days. The Twin Cities have added two heat waves and six dangerously hot days. Detroit has doubled its heat waves (from two to four) and doubled its hottest, most humid days (from three to more than six).
• Detroit has seen a rise in hot, dry air masses originating from the American Southwest, which were rare in the 1960s, now averaging more than five days per summer.
• Extreme heat is the leading weather-related cause of death in the United States, with high temperatures and humidity increasing risks of hyperthermia and dehydration, and aggravating conditions like diabetes and heart disease.

APA

Union of Concerned Scientists (2013). Heat in the Heartland. https://www.ucs.org/sites/default/files/2019-09/Heat-in-the-Heartland-2013-Update.pdf

Chicago

Union of Concerned Scientists. Heat in the Heartland. 2013. https://www.ucs.org/sites/default/files/2019-09/Heat-in-the-Heartland-2013-Update.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Heat in the Heartland |date=2013 |url=https://www.ucs.org/sites/default/files/2019-09/Heat-in-the-Heartland-2013-Update.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2013heat, author = {{Union of Concerned Scientists}}, title = {{Heat in the Heartland}}, institution = {Union of Concerned Scientists}, year = {2013}, url = {https://www.ucs.org/sites/default/files/2019-09/Heat-in-the-Heartland-2013-Update.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }