WGN-TV

Chicago’s largest temperature spread in a calendar year

Dear Tom,
What is the largest temperature spread Chicago has experienced in a calendar year?
George Schultz, Lake Forest
Dear George,
A huge spread in temperature extremes gives credence to the vigor of Chicago’s climate. Temperatures have spanned a 132 degrees over the course of the city’s 149-year climatological record, from a low of minus 27 on Jan. 20, 1985, to a high of 105 on July 24, 1934. While the extremes in a single year are not quite as robust, they are still very impressive. The year with the greatest range of extremes is 1985, when there was a 126-degree difference between the year’s high of 99 on Sept. 7 to the city’s all-time record low of minus 27 on Jan. 20. Runner-up was 1983, with a 125-degree spread from a high of 100 on July 22 to a low of minus 25 on Christmas Eve.