INDIANAPOLIS, Indiana — A dangerous heat risk is in place across Indiana, Illinois, Ohio and Kentucky for Wednesday, September 16, 2026, with major heat impacts possible from southern Indiana into Illinois and a moderate risk extending across much of central Indiana and Ohio. The heat risk map for Wednesday, September 16 shows a clear divide between the dangerously hot south and a noticeably cooler north, with cities like Madison, Wisconsin, Milwaukee, Wisconsin and La Crosse, Wisconsin sitting under minor or no heat risk while Evansville, Indiana, St. Louis, Missouri, Paducah, Kentucky and Carbondale, Illinois bake under the most intense heat impacts of the day.
What the Three Heat Risk Levels Mean for Residents
The heat risk map for Wednesday, September 16, 2026 uses three color-coded categories to describe the intensity of heat impacts across the region:
- Major Risk, shown in deep red, means heat impacts are possible for anyone outdoors without effective cooling preparations. This is not limited to vulnerable populations — healthy adults working or spending time outside without adequate water, shade and cooling are at real risk of heat illness under Major heat risk conditions.
- Moderate Risk, shown in orange, means heat impacts are expected for those sensitive to heat, including elderly residents, young children, outdoor workers and anyone with underlying health conditions that affect the body’s ability to regulate temperature.
- Minor Risk, shown in yellow, means heat impacts are possible for those sensitive to heat but conditions are less intense than the Moderate and Major zones to the south. Cities across Wisconsin, northern Illinois and northern Indiana and Ohio fall within the Minor Risk zone for Wednesday, September 16, 2026.
Cities Inside the Major Heat Risk Zone Wednesday
The following cities are visible within the deep red Major Heat Risk zone on the Wednesday, September 16, 2026 heat risk map:
- Evansville, Indiana sits within the Major Heat Risk zone for Wednesday, September 16, placing this southern Indiana city at the highest heat impact level on today’s map.
- St. Louis, Missouri falls within the Major Heat Risk zone and is one of the largest cities facing the most dangerous heat conditions on Wednesday, September 16, 2026.
- Carbondale, Illinois and Paducah, Kentucky are both visible within the Major Heat Risk zone on Wednesday’s heat risk map, sitting in the heart of the most intense heat footprint across the region.
- Bowling Green, Kentucky and Elizabethtown, Kentucky fall within the Major Heat Risk zone visible on the Wednesday, September 16 map.
- Louisville, Kentucky sits on the boundary between the Major and Moderate risk zones on Wednesday’s map, placing the city within reach of the most serious heat impacts of the day.
- Bloomington, Indiana is visible within or near the Major Heat Risk zone on the Wednesday, September 16, 2026 heat risk map.
Cities Inside the Moderate Heat Risk Zone Wednesday
The Moderate Heat Risk zone covers a broad area of central Indiana and Ohio on Wednesday, September 16, 2026. Cities visible within this zone include:
- Indianapolis, Indiana falls within the Moderate Heat Risk zone for Wednesday, September 16, with heat impacts expected for heat-sensitive residents across the metro area.
- Cincinnati, Ohio and Dayton, Ohio are visible within the Moderate Heat Risk zone on Wednesday’s map, sitting in the transition area between the most dangerous heat to the south and the lighter impacts to the north.
- Columbus, Ohio and Lima, Ohio fall within the Moderate Heat Risk zone for Wednesday, September 16, 2026.
- Lafayette, Muncie and Fort Wayne, Indiana are visible within the Moderate Heat Risk zone on Wednesday’s heat risk map.
- Lexington, Kentucky and Somerset, Kentucky fall within the Moderate Heat Risk zone on the Wednesday, September 16 map.
- Portsmouth and Athens, Ohio are visible within the Moderate Heat Risk zone for Wednesday, September 16, 2026.
- Huntington, West Virginia falls within the Moderate Heat Risk zone on Wednesday’s map, sitting along the southern Ohio and West Virginia border area.
- Pittsburgh, Pennsylvania is visible on the eastern edge of the Moderate Heat Risk zone for Wednesday, September 16, 2026.
- Peoria, Champaign, Springfield and Quincy, Illinois are visible within the Moderate Heat Risk zone on Wednesday’s heat risk map.
Cities Inside the Minor Heat Risk Zone Wednesday
Farther north, conditions become noticeably less intense as cooler air settles in. Cities visible within the Minor Heat Risk yellow zone for Wednesday, September 16, 2026 include:
- Chicago and Joliet, Illinois fall within the Minor Heat Risk zone for Wednesday, September 16, a sharp contrast to the Major and Moderate risks just to the south.
- South Bend, Indiana and Davenport, Iowa are visible within the Minor Heat Risk zone on Wednesday’s map.
- Toledo, Cleveland and Akron, Ohio fall within the Minor Heat Risk zone for Wednesday, September 16, 2026.
- Detroit, Lansing, Kalamazoo, Grand Rapids and Flint, Michigan are all visible within the Minor Heat Risk zone on Wednesday’s heat risk map.
- Rockford, Kenosha and Dubuque, Iowa fall within the Minor Heat Risk zone for Wednesday, September 16.
- Davenport, Iowa is visible within the Minor Heat Risk zone on Wednesday’s map.
Heat Safety Steps Every Resident Should Take Wednesday
Regardless of which risk zone you fall under on Wednesday, September 16, 2026, heat safety measures are essential across Indiana, Illinois, Ohio and Kentucky:
- Drink water consistently throughout the day and do not wait until you feel thirsty to hydrate, as thirst is already a sign of early dehydration.
- Avoid outdoor activity during the hottest afternoon hours if possible, particularly in Evansville, St. Louis, Paducah and Louisville where Major Heat Risk conditions are in place.
- Check on elderly neighbors and family members who may not have adequate cooling at home, as the Moderate and Major heat risk zones cover millions of residents across the four-state area on Wednesday, September 16, 2026.
- Never leave children or pets in vehicles under any circumstances on a Major Heat Risk day.
