Chicago, IL – Northern Illinois will see summerlike warmth carry through the end of the work week, with showers and storms possible over the weekend.
According to the US National Weather Service in Chicago, highs are expected to reach between 85 and 90 degrees on Thursday, September 18, with slightly cooler conditions near Lake Michigan. The warmth continues Friday, with inland highs in the upper 80s to near 90, while lakeside communities remain in the 70s.
The forecast shows increasing rain chances late Friday along the I-39 corridor, with scattered showers and thunderstorms possible Saturday and Sunday afternoons. The Weather Service notes that rain coverage will remain limited at 20–30%, meaning the weekend won’t be a washout, but outdoor plans could be briefly interrupted.
Saturday highs will range from 82 to 87 degrees, and Sunday will stay warm with highs between 81 and 85. Overnight lows through the weekend are expected in the low to mid-60s.
Forecasters added that winds off Lake Michigan will keep conditions noticeably cooler for lakeshore areas through Saturday. Residents planning outdoor activities are advised to keep umbrellas nearby as isolated showers and storms may develop, especially in the afternoons.
Commuters and eventgoers across Chicago, Cook County, and the wider northern Illinois region should monitor local forecasts for updated storm timing.
