Chicago, Illinois – Oppressive heat and humidity will blanket Illinois starting Saturday, with heat indices topping 100°F across much of the state and overnight lows offering little relief, especially in Chicago.
According to the National Weather Service in Chicago, this will be the most intense stretch of summer heat so far, peaking from Saturday through Monday. Heat indices between 100–107°F are expected in Chicago, Joliet, Aurora, and surrounding areas during the late afternoon. Overnight lows will remain in the mid to upper 70s, with some urban zones—particularly in Cook County—staying above 80°F well past midnight.
City residents are urged to stay hydrated, limit outdoor activity, and use air conditioning if available. The combination of high temperatures and relentless humidity will create dangerous conditions for those without access to cooling, with Chicago issuing an Extreme Heat Warning for all of Cook County. Urban heat effects will intensify the risk after sunset, especially in densely built neighborhoods.
Public health officials advise checking on elderly relatives and neighbors and calling 3-1-1 to locate nearby cooling centers. This heat wave may extend into Tuesday, depending on how quickly humidity levels retreat.
⚠️ Excessive heat warnings remain in effect through at least Monday night. More advisories may be issued.
