What is the Chicago record for 90-degree days?

Dear Tom,

Chicago is closing in on 20 days in the 90s this year. What is the record?
— William Girard, Shorewood
Dear William,
Using the city’s official station data, Chicago climatologist Frank Wachowski reports that the most 90-degree-plus days for any year was 47, recorded in the 1988 drought summer. That same summer Midway Airport unofficially logged 48. The fewest occurrences are all linked to years when the official thermometer was located near the lake. In 1875, there were no 90-degree days, the only time this has happened since climate records began in 1871. There were three summers with just one: 1882, 1884 and 1915. The city’s longest string of days of at least 90 degrees is 11, logged on four occasions, all during the torrid summers of the 1950s: Aug. 24-Sept. 3, 1953; June 11-21, 1954; July 26-Aug. 5, 1955; and Aug. 19-29, 1959.