It seems the city’s normal low was 64 degrees for a very long time. Was it?
It sure was, but now it’s fallen to 63. Based on the city’s latest climate normals, derived from 1981-2010 data, Chicago’s normal low temperature reaches a year’s high of 64 degrees for an extended 38-day period from July 7-Aug. 13. Beyond that, there is a slow decline through the rest of the year falling to the freezing mark on Nov. 16 and continuing to drop to the year’s minimum of 16 degrees during the period from Jan. 11-27. At that point, the low temperature begins its annual climb, breaking above freezing on March 27, then rising to 44 degrees on May 1, 53 degrees by June 1, and finally returning to its annual peak of 64 degrees on July 7.