Chicago, Ill. – Residents across northern Illinois and northwest Indiana face a double weather threat through Monday as unhealthy wildfire smoke lingers before strong to severe thunderstorms move into the region Monday evening with damaging winds and torrential rainfall.
According to the National Weather Service in Chicago, poor air quality caused by Canadian wildfire smoke will continue through Monday, prompting an Air Pollution Action Day across Illinois and northwest Indiana. Officials urge residents to reduce prolonged or strenuous outdoor activity, especially those with asthma, heart disease or other respiratory conditions, and monitor real-time conditions at AirNow.gov.
Attention then turns to Monday evening as a cold front approaches. Forecasters say there is growing concern for severe thunderstorms capable of producing damaging wind gusts exceeding 70 mph, brief tornadoes, and locally torrential rainfall that could lead to isolated flash flooding. While confidence is increasing that severe weather will develop somewhere in the region, the exact storm track remains uncertain.
The highest threat window begins between 5 p.m. and 1 a.m. across north-central Illinois, including Rockford and DeKalb, expands into the Chicago metro from 7 p.m. to 3 a.m., and continues into northwest Indiana between 9 p.m. and 5 a.m. Communities including Chicago, Aurora, Joliet, Waukegan, Kankakee, Valparaiso and Gary should closely monitor forecast updates throughout Monday.
Residents should charge electronic devices, secure outdoor furniture and have multiple ways to receive weather warnings before going to bed. Drivers should be prepared for sudden visibility reductions, ponding on roads and possible downed tree limbs during the overnight hours.
Cooler weather follows the storms, with highs easing into the low to mid-70s Wednesday before rebounding to the upper 70s and lower 80s later in the week. A high swim risk is also expected along Lake Michigan beaches Tuesday and Wednesday due to dangerous waves and currents.
Four-Day Forecast for Chicago, Illinois
- Monday: Severe thunderstorms possible during the evening. High 83–87°F. Low 70–75°F.
- Tuesday: A few morning showers. High 82–86°F. Low 58–67°F.
- Wednesday: Sunny and cooler with a high swim risk along Lake Michigan. High 73–77°F. Low 54–64°F.
- Thursday: Mostly sunny. High 77–81°F. Low 57–68°F.
