Chicago, Illinois – Steamy temperatures and rising humidity will make for a sweltering midweek across Illinois, with heat indices nearing 100°F and afternoon thunderstorms likely by Wednesday and Thursday.
According to the National Weather Service Chicago, dry conditions Monday will give way to increasingly humid air by Tuesday, especially south of I-80, where highs will climb into the low 90s. Thunderstorm chances begin creeping in Tuesday afternoon (20-40%) but increase significantly Wednesday (40-50%) and Thursday (50-70%), particularly during the late-day hours.
Localized storms may bring downpours, lightning, and gusty winds, especially in areas along and east of I-55. Commuters should prepare for slowdowns during the afternoon rush and remain weather-aware, as conditions could shift rapidly. Temperatures will stay warm overnight, offering little relief with lows in the upper 60s to low 70s.
Residents are advised to stay hydrated, avoid extended outdoor activity during peak heat, and secure outdoor items ahead of potential gusty winds. This humid pattern could stick around into late week, with more storms possible beyond Thursday.
Five-Day Forecast for Northern Illinois:
- Monday: Sunny, dry. Highs 84–90°F. Lows 65–71°F.
- Tuesday: Humid with isolated PM storms (20–40%). Highs 84–91°F. Lows 68–74°F.
- Wednesday: Humid, scattered storms (40–50%). Highs 86–91°F. Lows 67–73°F.
- Thursday: Storms likely (50–70%), especially PM. Highs 78–88°F. Lows 61–69°F.
- Friday: Partly cloudy, drier. Highs 75–83°F. Lows 60–68°F.
