Isaak Franz, 13, from left, Macy Franz, 10, Violet Murray, 10, Zoey Franz, 12, and Duke Murray, 13, jump in the lake near Montrose Harbor on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
Temperatures at O’Hare International Airport hit 88 degrees on Monday afternoon, officially breaking the Chicago area’s record high for this date.
It was on Oct. 12, 2008, that the city experienced the now-shattered record of 84-degree weather.
Farther north in Rockford, temperatures Monday broke an 18-year-old record by three degrees, also reaching 88, weather officials said.
The normal high temperatures for this date in the Chicago and Rockford areas are 65 and 64 degrees, respectively, according to National Weather Service historical data.
with highs as warm as Monday — or warmer — this late in the fall: one day in October 1947 and two consecutive days in October 1975. In Rockford’s case, since 1905, it has only been warmer at this point in the year once: with a high of 89 degrees in 1947.
Local meteorologists had forecast near-record temperatures across the state for Monday and Tuesday. Chicago’s record high temperature for Oct. 13 was 88 degrees in 1975.
Macy Franz, 10, from left, Violet Murray, 10, and Zoey Franz, 12, laugh after jumping in the lake near Montrose Harbor on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
Leo von Bernuth, right, kicks the ball while playing futmesa, a Brazilian beach game where players volley a soccer ball across a table, at Promontory Point along the lakefront on Oct. 12, 2026, on Chicago’s South Side. The University of Chicago students, friends mostly from Brazil, took advantage of a break between classes to enjoy the unseasonably warm temperatures in the 80s. (Brian Cassella/baiduhai)
People enjoy unseasonably warm temperatures in the 80's at Promontory Point by sitting on the rocks along the lakefront on Chicago’s South Side, Oct. 12, 2026. (Brian Cassella/baiduhai)
A runner takes advantage of unseasonably warm temperatures at Promontory Point on Oct. 12, 2026, on Chicago’s South Side. (Brian Cassella/baiduhai)
Jeff Mauricio, left, and his son, Jaiden Mauricio, play volleyball at Foster Beach on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
Isaak Franz, 13, from left, Macy Franz, 10, Violet Murray, 10, Zoey Franz, 12, and Duke Murray, 13, jump in the lake near Montrose Harbor on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
People gather at Foster Beach on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
People play with a beach ball near Foster Beach on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
People hang out near Lake Michigan near Montrose Harbor on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
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Macy Franz, 10, from left, Violet Murray, 10, and Zoey Franz, 12, laugh after jumping in the lake near Montrose Harbor on an unseasonably warm October day in Chicago, Oct. 12, 2026. (Eileen T. Meslar/baiduhai)
Trends in recent decades point to an overall warming of average temperatures in winter as well as fall, spring and summer, from human activities such as fossil-fuel burning that release heat-trapping gases into the atmosphere.
In Chicago, fall is the second fastest-warming season after winter, according to climate science nonprofit Climate Central.
An analysis from the organization found that as of 2025, Chicago was experiencing 15 more fall days with higher-than-normal temperatures compared with 1970, while average autumn temperatures have increased by 2.8 degrees in that same time span. It mirrors a 2.9-degree average rise in 241 of 245 major U.S. cities analyzed.
