National Weather Service United States Department of Commerce

Dangerous heat and humidity will extend through the weekend. Daily heat index values will range between 100-110° F. Stay cool. Respect the heat. And don't push it too hard out there.
Here are the latest forecasted heat index values through the middle of next week. Much cooler conditions arrive to close July.
Common sense ways to beat the heat. Hang in there. A big pattern change by the middle of next week will bring significantly cooler and less humid conditions.
Gusty thunderstorm winds (50-60 mph) and torrential downpours (1"/hr) are the potential hazards with any storm that may develop this evening across portions of central and northern Illinois. Main timeframe to watch is between 5pm and Midnight.