Chicago, Illinois – Dangerous heat and humidity will grip Chicago and much of northern Illinois through Thursday night, with peak heat indices soaring between 100 and 110°F and no relief expected overnight. Residents are urged to stay indoors and limit outdoor activity, as the combination of sweltering temperatures and humidity poses a significant health risk.
According to the National Weather Service Chicago, the most hazardous conditions will occur Wednesday afternoon through Thursday evening, when scattered thunderstorms may develop at any time. The risk of severe storms and torrential rainfall will ramp up late Thursday, continuing into Friday and Saturday, potentially causing localized flash flooding—especially in urban and low-lying areas.
In Chicago, Aurora, Joliet, and Rockford, heat indices could exceed 105°F during the day, while overnight lows will remain uncomfortably warm above 75°F. Major roadways like I-90 and I-55 may see reduced visibility and ponding water if storms materialize. Residents should hydrate, check on vulnerable neighbors, avoid non-essential travel, and charge devices ahead of possible power outages.
This is the first prolonged heatwave of the season, reminiscent of similar July extremes in recent years. The most intense heat will ease by Friday as rain chances increase, but scattered storms and flash flood threats will linger through Saturday. Additional weather alerts may be issued as conditions evolve. Stay tuned for updates.
