A four-day Extreme Heat Warning is in effect for northern Indiana, lower Michigan and northwest Ohio today through Thursday evening, as heat index values up to 105°F and overnight lows that refuse to drop below the mid-70s create a mounting heat load that will peak just as the Fourth of July weekend gets underway.
The Warning: Monday Through Thursday
Two NWS offices have issued coordinated Extreme Heat Warnings, both running from 2 PM EDT Monday through 8 PM EDT Thursday — the day before July 4th.
The National Weather Service in Northern Indiana covers northern Indiana, southwest Michigan and northwest Ohio, with heat index values up to 105°F expected daily.
The NWS Grand Rapids office covers central, south-central and western Michigan with the same 105°F forecast. An Extreme Heat Warning is the highest tier of heat alert the NWS issues — reserved for conditions where heat illness is expected to occur rapidly even in otherwise healthy adults.
Northern Indiana: Fort Wayne, South Bend and the Corridor
The Northern Indiana warning spans from the Illinois border east to the Ohio state line, covering Fort Wayne, South Bend, Elkhart, Kokomo, Logansport, Wabash, Angola, Huntington, Bluffton and Marion.
Southwest Michigan counties — Cass, St. Joseph, Branch, Hillsdale and both Berrien zones — are included. In northwest Ohio, the warning covers the Lima, Defiance, Bryan and Wauseon corridors.
Michigan: Grand Rapids, Lansing, Kalamazoo and the Lake Shore
The Grand Rapids warning covers 23 counties across lower Michigan’s most populated region: Grand Rapids, Lansing, Kalamazoo, Battle Creek, Holland, Muskegon, Jackson, Mount Pleasant and Ludington. The west Michigan shoreline (Holland, Grand Haven, Muskegon) and the Lansing metro are both included.
No Overnight Relief: The Key Medical Concern
The detail that turns a heat advisory into a sustained health emergency: “Overnight lows in the mid-70s will offer limited relief from the heat,” the NWS Northern Indiana office stated. When overnight temperatures stay above 75°F, the body cannot fully shed the heat load accumulated during the day. Each successive night that brings no cooling adds to the cumulative burden — and by Thursday (day four), anyone without reliable air conditioning will have been physiologically stressed for four consecutive days with no recovery.
That four-day accumulation is what makes this warning medically significant beyond its peak heat index number.
Staying Safe Through Thursday and Into the Holiday
The warning runs through Thursday, 8 PM EDT — the eve of July 4th. Anyone planning outdoor Fourth of July events on Friday should note that this heat wave is not clearing before the holiday, only briefly pausing before the broader Midwest heat watch picks up where this warning leaves off.
Stay in air-conditioned spaces between 2 PM and 8 PM daily, drink water continuously, check on elderly neighbors every day of the warning, and never leave children or pets in a parked vehicle. For cooling center locations in Indiana, contact your county emergency management office or dial 211. Track updates at weather.gov/iwx and weather.gov/grr.
