Has May, June or September ever been the hottest month of the year at Chicago?

Dear Tom,
Has May, June or September ever been the hottest month of the year at Chicago?
Nick Recchia, River Grove
Dear Nick,
In 148 years of Chicago temperature records (from 1871 through 2018), May has never been the warmest month of any year. June has been the warmest month of the year on three occasions: in 1933, 1967 and 1971. The average June temperature in 1933 was 76.2 degrees, beating July’s 75.6 degrees and August’s 71.5 degrees; in 1967, June averaged 71.4 degrees, beating runner-up July with 70.6 and August with 69.2 degrees; and in 1971, June was 75.8 degrees versus July with 72.6 degrees and August with 72.4 degrees. September was the warmest month of the year only once, in 1884, with 68.7 degrees. It was a cool summer in 1884: June averaged 64.2, July 68.5 and August 68.2. In the remaining 144 years, July or August was the warmest month of the year.

Notice: you are using an outdated browser. Microsoft does not recommend using IE as your default browser. Some features on this website, like video and images, might not work properly. For the best experience, please upgrade your browser.