Chicago Breaks October Heat Record Before Cold Front Arrives

Chicago and Rockford set daily temperature records on Monday, Oct. 12, 2026, as both cities reached 88 degrees during an unusually warm October day, according to the Chicago Tribune and local weather officials.

Temperatures at O’Hare International Airport officially surpassed Chicago’s previous Oct. 12 record of 84 degrees set in 2008, while Rockford exceeded its 18-year-old record by three degrees, according to weather officials.

The National Weather Service historical data shows normal high temperatures for this date are 65 degrees in Chicago and 64 degrees in Rockford. The warmth was more than 20 degrees above normal for the area.

NBC Chicago reported that meteorologist Iisha Scott of the NBC 5 Storm Team forecast a warm start to the week followed by a sharp temperature decline.

"A summer feel to start the week," said Iisha Scott, NBC 5 Storm Team Meteorologist.

Scott described the later shift as a major change after the early-week warmth. The forecast called for temperatures to remain high Tuesday before a cold front moved through Wednesday.

"Really big temperature drop," said Iisha Scott, NBC 5 Storm Team Meteorologist.

The weather pattern was expected to bring rain and storms after sunset Tuesday, with some stronger storms possible near counties around I-39, according to Fox 32 Chicago.

"You'll at least notice it," said Iisha Scott, NBC 5 Storm Team Meteorologist.

Scott was referring to humidity levels during the warm spell, which included dew points in the 50s and 60s. She said conditions would not be unusually humid for temperatures in the mid-80s.

"But it won't be terribly high for what you'd normally expect with temperatures in the mid-80s," said Iisha Scott, NBC 5 Storm Team Meteorologist.

Chicago’s late-season heat was also unusual historically. According to the Chicago Tribune, Chicago has recorded only three other days since 1871 with highs at least as warm this late in fall.

Those earlier occasions included one day in October 1947 and two consecutive days in October 1975. Rockford has only been warmer once since 1905, reaching 89 degrees in 1947.

The cold front was expected to lower temperatures into the 60s Wednesday and Thursday, with highs potentially reaching only the upper 50s by Friday, according to NBC Chicago.

"We go from 85 Monday to 58 for a high on Friday," said Iisha Scott, NBC 5 Storm Team Meteorologist.

The Chicago Tribune reported that recent decades have brought more above-normal fall days in Chicago. An analysis cited by the newspaper found Chicago had 15 more unusually warm fall days in 2025 than in 1970.