A dangerous and prolonged heat dome is set to trap scorching air across a massive stretch of the United States from June 28 through July 2, sending heat index values surging to potentially deadly levels in dozens of cities — and forecasters say this is not a storm you can simply wait out.
St. Louis Could Feel Like 111 Degrees
At the epicenter of this unfolding heat emergency, St. Louis is forecast to reach a heat index of 111 degrees by Monday afternoon, June 29 — a level that can cause heat stroke in healthy adults within minutes of unprotected exposure. That is not the temperature. That is what the air will feel like on your skin.
The numbers across the region are equally alarming:
- Des Moines, IA — 108°F heat index
- Memphis, TN — 108°F heat index
- Evansville, IN — 108°F heat index
- Jefferson City, MO — 108°F heat index
- Nashville, TN — 106°F heat index
- Peoria & Springfield, IL — 106°F heat index
- Augusta, GA — 106°F heat index
The Heat Does Not Stop at the Midwest
What makes this event particularly dangerous is its geographic reach. The heat dome stretches far beyond the Plains and Midwest, pushing deep into the Ohio Valley, Great Lakes, Southeast, and Mid-Atlantic.
Indianapolis, Cincinnati, Columbus, Cleveland, and even Minneapolis are all expected to hit heat index values near or above 99 degrees. Charlotte and Charleston are forecast to climb to 100 degrees. The affected population spans tens of millions of residents.
This Could Turn Deadly — Here Is What You Need to Do Right Now
Forecasters are issuing urgent warnings for the entire June 28–July 2 window. The risk is not limited to a single hot afternoon — this heat is expected to build and persist for five consecutive days, giving the body little opportunity to recover overnight.
- Stay indoors during peak hours between noon and 6 p.m.
- Drink water consistently — do not wait until you feel thirsty
- Never leave children, elderly individuals, or pets in parked vehicles
- Check on neighbors, especially those living alone or without air conditioning
- Know the signs of heat stroke: confusion, no sweating, and skin that is hot to the touch
If you or someone around you stops sweating during extreme heat, call 911 immediately.
