Wisconsin cities from Madison to Milwaukee and up to Wisconsin Dells could see extreme temperatures this week as a heat wave moves across the Midwest and eastern United States.
According to the National Weather ServiceFor Southeastern Wisconsin, “heat effects are expected during the work week, with heat index values 95 to 110 degree range Every day Mon. According to the NWS, the extreme heat is expected to continue through the July 4 weekend, and extreme heat warnings are in place for much of the state, with “dangerously hot conditions, with daytime heat index values expected to reach 107 each day and nighttime heat index values only in the upper 70s.”
WTMJ-TV in Milwaukee It was warned that the heat wave could be “deadly”.
It will be very hot and humid on Monday off the coast of Lake Michigan. Afternoon highs will reach the upper 80s to mid 90s, with a heat index of 95-105 degrees in many areas. #wiwx pic.twitter.com/BV9kTitMvk
– NWS Green Bay (@NWSGreenBay) 27 June 2026
“Heat is a silent killer,” said Storm Team 4 meteorologist Brendan Johnson. To WTMJ. “It’s one of the top weather-related killers in our country, and it’s certainly at the top of the list in the Badger State.” The Milwaukee Health Department has published List of cooling sites.
Wisconsin weather forecast warns of possible ‘prolonged heat’ that could reach a heat index of 110 degrees in many cities
Extreme heat is expected on Monday and Tuesday with the heat index ranging from 90 to above 107 degrees on both days. Apart from this, rain with occasional thunderstorms is also forecast till Tuesday. Stay hydrated! pic.twitter.com/Smx0IZfklW
– NWS Green Bay (@NWSGreenBay) 28 June 2026
The National Weather Service is predicting a “long heat wave next week” for several major cities in Wisconsin, According to its website. Wisconsin Dells, Fond du Lac, Beaver Dam, West Bend, Madison, Janesville, Milwaukee and Kenosha were among the cities where temperatures could exceed 100 degrees. Monday 29 June and Tuesday 30 June were predicted to be the warmest.
(Photo by Vincent D. Johnson/Xinhua via Getty Images)
The extreme heat is expected to last through the July 4 weekend. National Weather Service Weather Prediction Center released a map on June 28, which also showed a forecast of dangerous heat covering Wisconsin for July 1 to July 5.
An updated Day 3-7 Threat Outlook has been issued. https://t.co/VBxTZCp4sE pic.twitter.com/REd4xP3Qpn
– NWS Weather Prediction Center (@NWSWPC) 28 June 2026
“Even near Lake Michigan, little respite from the heat!” Wednesday and Thursday may be less warm with more clouds and a few showers and storms “from time to time,” the NWS wrote, adding that temperatures those days could still be in the high 90s.
National Weather Service warns of ‘significant, dangerous’ heat wave
The Eastern United States and the Midwest should prepare for a “significant, dangerous and record-breaking heat wave” that is “expected for the eastern US in the mid to late next week.” The NWS wrote with its national forecast.
“The latest guidance continues to strongly agree on a potential historic heatwave across the eastern third of the country by the end of the week, and all guidance has a closed 594dm contour that will persist for a few days. Some guidance hints at the possibility of an all-time record high, which will peak during the Thursday to Friday time period.” Reads the national forecast.
“This period will begin on Wednesday when a strong mountain range remains in place in the eastern part of the country, supporting a massive and dangerous heat wave,” the forecast predicted.
“Meanwhile an extended trough will prevail over the west as several impulses advance within the flow, with some of the energy possibly suppressing the eastern ridge a bit by next weekend. The Gulf Coast/Florida area, southern Rockies and upper Midwest to the Great Lakes/Northeast will have the greatest potential for showers and storms.”
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