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Monday night’s temperatures could be the highest since 1973 for Aug. 27.

Although the National Weather Service issued a heat advisory for the Chicago area Monday

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, and by late afternoon temperatures hit the mid-90s at O’Hare International Airport, temperatures were still a few degrees short of the record high for the day of 97 degrees.

But according to the weather service, evening temperatures could top the record-high minimum temperature for the day.

“It’s going to stay really warm tonight,” said weather service meteorologist Ricky Castro. “There’s a good chance that we won’t drop much this evening.”

The record-high minimum temperature for Aug. 27 is 77 degrees and was set in 1973, Castro said. At this point in August, overnight temperatures are generally in the low- to mid-60s.

“And our lowest so far today was 78, so if we don’t drop below 78 before 12:59 a.m. tonight … we’ll actually have a new record-high minimum temperature for the day,” he said.

The combination of southwesterly winds and high humidity will help keep temperatures from dropping, said Castro.

But the heat should subside by Wednesday.

“Wednesday night will be a really pleasant night,” Castro said. “You can turn off the AC and open up the windows. And Thursday will be another nice night. And Friday won’t be too bad.”

The heat advisory includes counties in northern Illinois and northwest Indiana, including Cook, DuPage, Will and Kane counties, as well as Lake County, Ind., and 13 other Illinois counties. Cities affected include Aurora, DeKalb, Dixon, Elgin, Oregon and Wheaton, and was scheduled to last until 7 p.m. Monday. Chicago residents can call 311 to request well-being checks for elderly friends or family members, or for information on the closest cooling center.

Check the Tribune’s weather page for updates on the forecast.

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