A recent question addressed the city’s hottest summers. What have been the coolest?
Don & Susi Kiefer
Dear Don and Susi,
Chicago’s coolest summers occurred early in the city’s climate history, when the official thermometer was in various downtown locations, all near Lake Michigan. The coolest summer was in 1875, one that averaged 66.6 degrees and ranks as Chicago’s only summer without a 90. Runner-up cool summers were 1915, that averaged 66.9 degrees with one 90 and 1884 at 67.0 degrees, with one 90-degree day. Since the thermometer was moved to Midway Airport in 1942 and then to O’Hare in 1980, the coolest summer was in 1992, a year marked by worldwide cooling, the result of the massive eruption of Mt. Pinatubo in the Philippines. That summer averaged 67.1 degrees and posted six 90s.