Dear Tom,

Chicago is known for its wild temperature swings. What is the city’s longest string of days with highs of at least 70 degrees?

Sammy Rollins

Dear Sammy,

Chicago is famous for its large day-to-day temperature fluctuations, often exacerbated in the spring by the chilly waters of Lake Michigan. Earlier this May, the mercury surged into the summer-like 80s and 90s after several chilly days in the 50s. We had Chicago climatologist Frank Wachowski check the archives and he found the city’s longest run of days with highs of at least 70 was 117, extending from May 29-September 22, 2005. The mercury reached 70 degrees on May 29 and topped 70 every day until September 23 when the high was only 67. The hottest day during this stretch was a scorching 102 on July 24. The runner-up spell of 70-plus days was 110 from June 8-September 25, 2016.