Chicago, Illinois – Sweltering humidity combined with unstable air could spark severe thunderstorms across northern Illinois on Wednesday, bringing a risk of damaging winds, torrential rain, and localized flooding.
According to the National Weather Service Chicago, the region will turn increasingly hot and humid heading into midweek. Wednesday is expected to be the most dangerous day, with a 70 to 80% chance of strong to severe storms developing during the afternoon and evening. Areas from Chicago to Rockford and along the I-90 corridor are especially vulnerable.
The extreme humidity will push heat index values near 95°F in some locations. Forecasters warn the combination of tropical-like air and an approaching cold front could trigger fast-moving storms capable of downed trees, power outages, and rapid ponding on roads. Counties at greatest risk include Cook, Lake, McHenry, Kane, and DuPage.
Tuesday will offer a preview, with highs near 90°F and scattered storm chances, but Wednesday brings the most serious threat. Residents should prepare for possible warnings, review emergency plans, and avoid travel during peak storm hours.
Storm alerts may be issued quickly—stay connected for updates through Wednesday evening.
🌡️ Five Day Forecast for Northern Illinois (June 15–19):
- Sunday: Partly cloudy, highs 76–84°F; cooler near lake. Lows 59–65°F.
- Monday: Mostly sunny, highs 82–87°F; 20% storm chance northwest. Lows 63–68°F.
- Tuesday: Very humid, highs 87–91°F; 30–50% chance of PM storms. Lows 65–69°F.
- Wednesday: Extreme humidity, 70–80% chance of severe storms. Highs 80–84°F. Lows 62–67°F.
- Thursday: Drier with highs 80–84°F, partly cloudy. Lows 61–65°F.
