Chicago, Illinois – Heat index values could soar to 105 degrees across northern Illinois and northwest Indiana this weekend, with high humidity and little overnight relief prompting a heat advisory from 10 a.m. Saturday until midnight Monday.
According to the National Weather Service in Chicago, the advisory covers a wide swath of the region including Rockford, Joliet, Kankakee, and Valparaiso. Air temperatures in the low to mid-90s, combined with oppressive humidity, will drive up the heat index. Overnight lows will hover in the mid-70s, increasing the risk for heat exhaustion, especially in areas without air conditioning.
Cities like Aurora, Waukegan, and Merrillville could see multiple days of dangerous heat levels, particularly between 2 p.m. and 7 p.m. each afternoon. Residents are urged to limit outdoor activity, stay hydrated, and check on vulnerable neighbors. Cooling centers may be opened in some counties, and schools holding summer sessions may adjust schedules.
The advisory comes amid one of the region’s earliest extended heat waves in recent years, with a similar stretch last seen in June 2021.
The heat is expected to break late Monday, but additional advisories may be issued if temperatures remain elevated.
