Milwaukee, Wisconsin – A relentless dome of heat and humidity will blanket southeast Wisconsin starting Wednesday morning, pushing heat index values as high as 107° and triggering an Extreme Heat Watch for much of the state until 7 p.m. Thursday. Daytime highs are expected to surge into the lower to mid-90s, and even Lake Michigan’s shoreline communities will see little relief.
According to the National Weather Service Milwaukee/Sullivan, gusty southwesterly winds will fuel both the heat and humidity, with the most intense conditions on Wednesday and a slightly lower—but still dangerous—heat risk on Thursday due to possible storms. Heat alerts stretch from Madison to Milwaukee, with cities like Waukesha, Racine, and Sheboygan facing maximum heat indices over 100°. Roadways may become hazardous as vehicle and rail systems face extra stress; residents are urged to limit time outside, check on vulnerable neighbors, and keep pets indoors.
In addition, beaches along Lake Michigan in Ozaukee and Sheboygan Counties are under a High Swim Risk advisory. Southeast winds up to 20 mph and 4-foot waves will create life-threatening currents, especially near piers and break walls. The safest choice is to stay out of the water—if you must swim, use a life jacket and avoid risky areas.
These dangerous conditions come as heat remains one of the top weather-related killers in the U.S. Anyone without access to air conditioning should seek local cooling centers and stay hydrated. The heat wave may ease Thursday evening with cloud cover and thunderstorms, but more alerts could follow if the pattern lingers.
Five-Day Forecast for Southeast Wisconsin:
- Wednesday: Sunny, highs 93–96°, heat index up to 107°, breezy SW winds.
- Thursday: Partly cloudy, highs 90–94°, heat index 98–103°, chance of p.m. storms.
- Friday: Scattered showers, cooler, highs 82–85°.
- Saturday: Mostly sunny, highs 80–83°, lower humidity.
- Sunday: Pleasant, highs 78–81°, light winds.
