Has it ever hit 100 degrees in Chicago in May?
It has, but not at the city’s official station. Based on official site records, Chicago’s temperature has never reached triple-digits in May, the month’s highest reading being 98 on May 31, 1934. But it did reach triple digits the next day, when the mercury soared to 102 on June 1. In 1934, however, the official thermometer was at the University of Chicago, close to the cooling breezes of Lake Michigan. Inland temperatures on May 31 were higher: Midway Airport reached 102, Aurora 104, Joliet 101, LaSalle 105, and Rockford and Marengo both hit 107. That early-season heat wave marked the beginning of a torrid “dust bowl” summer during which the city would officially log four 100-degree days, while inland Midway Airport documented a record-tying 11 days.