What is Chicago’s temperature variation during the course of the year?
Chicago’s temperatures range from 31/16 degrees in mid-January to 85/64 degrees in mid-July. That is a range of 51 degrees from the coldest January days to the warmest July days. Those are average temperatures, but Chicagoans know that the actual temperatures that the city experiences exhibit considerably greater ranges. The highest reading ever recorded here is 109 degrees on July 23, 1934, at Midway Airport (but the official high that day was 94 at the University of Chicago, which picked up an afternoon lake breeze that kept the day’s high much lower). Chicago’s lowest temperature is 27 degrees below zero, recorded at O’Hare International Airport on Jan. 20, 1985.