"We do have some spots that will be dropping back into the 30's," ABC7 Meteorologist Tracy Butler said. "Even possibly in the city, may be dropping back into the mid-40's."
If the temperature falls to 40-degrees or below, it'll be a new record low.
"It looks like we are really going to come close, perhaps break it," Butler said. Watch Tracy Butler's Forecast
"It's very possible far away from the city there could be some patchy frost," Butler said, so suburban gardeners might want to bring in houseplants that were outside for the summer and cover up vegetable and flower gardens with a large bed sheet.
Frost is not expected in the city, and soil temperatures will remain in the 60's across the area.
The last time the Chicago saw 30-degree temperatures was in April.