Chicago, Illinois – A sharp drop in temperatures will sweep into northern Illinois late this weekend as a cold front pushes across the region, sending highs into the low 70s and overnight lows into the upper 40s by Monday. Breezy conditions and isolated showers may develop Saturday afternoon, with a chance of lightning southeast of I-57 before drier air settles in.
According to the National Weather Service Chicago, the front will bring unseasonably cool air more typical of late September. While Sunday through Tuesday is expected to remain largely dry, forecasters note that some lake-effect sprinkles could form near northwest Indiana early in the week.
Daytime highs in Chicago will struggle to reach 74 degrees Sunday, dropping further into the upper 60s by Monday and Tuesday. Lows will dip into the 40s in outlying suburbs, with Chicago and lakefront areas staying slightly warmer. Breezy northwest winds will make conditions feel cooler, especially Sunday.
Travelers along I-55 and I-57 should watch for brief showers and possible lightning Saturday afternoon. Residents are advised to keep jackets and layers handy as temperatures fall to their lowest levels since spring.
Cooler-than-normal conditions are expected to last through at least Tuesday, with additional updates possible if lake-effect showers strengthen.
Five Day Forecast for Chicago, Illinois
- Saturday: Breezy, scattered showers possible, highs 77–83, lows 52–62
- Sunday: Mostly sunny, highs 70–74, lows 47–58
- Monday: Sunny, highs 68–72, lows 46–57
- Tuesday: Partly cloudy, highs 69–73, lows 47–58
- Wednesday: Continued cool, partly sunny, highs near 72, lows in the upper 40s to low 50s
