ASK TOM: January 1985's -27 degrees below zero in Chicago

Dear Tom,
I remember some time in the 1980s when Chicago’s temperature hit 27 degrees below zero, but a friend refuses to believe it has ever been that cold here. Please set him straight.

— Larry Ecker, Chicago


Dear Larry,


That Chicago has ever recorded a temperature of 27 degrees below zero might seem to exceed the limits of credibility, especially because recent winters have had difficulty producing a reading as low as 10 below zero, but your memory of 27 degrees below zero is correct.
On the morning of Jan. 20, 1985, the city’s official thermometer plunged to 27 below, Chicago’s lowest temperature ever. Coupled with winds of 15 to 30 mph, wind-chill temperatures hovered near 80 below. (The wind-chill formula has been restructured, and today that would be 57 degrees below zero.)