A dangerous heat dome has locked in place across the southern United States, sending temperatures soaring across major highway corridors from the Desert Southwest to the Carolinas. More than 72 million Americans are under some form of heat alert, with feels-like temperatures reaching 117°F in parts of the South.
Peak danger window: Thursday afternoon through Sunday, when Extreme Heat Warnings stack across I-10, I-20 and I-40 corridors and overnight lows fail to drop below 80°F in major metro areas.
Where the Extreme Heat Is Worst
NWS Phoenix has issued an Extreme Heat Warning through Friday evening for parts of southwest Arizona and southeast California. Afternoon temperatures are forecast at 107 to 114°F, with overnight lows only reaching 88 to 92°F. The atmospheric ridge over the region is running near the 97th percentile of climatology, which means this is a near-record-strength heat pattern for late August.
NWS Fort Worth has Extreme Heat Warnings active for northeast Texas into southern Oklahoma and Arkansas today. Feels-like temperatures across the South are running 110 to 117°F, with heat indices topping 115°F in parts of Tennessee, Arkansas, Mississippi, Missouri, Illinois, Iowa, Kansas, Nebraska and Oklahoma.
Miami hit 100°F on Tuesday, only the second time in the city’s recorded history since 1895. The only previous occurrence was July 21, 1942.
Highway Corridors Directly Impacted
- I-10: Phoenix through Tucson, El Paso, San Antonio, Houston, New Orleans and Jacksonville
- I-8: Yuma to El Centro, at the epicenter of the Extreme Heat Warning zone
- I-20: Dallas-Fort Worth through Shreveport, Jackson and Atlanta
- I-40: Oklahoma City through Little Rock, Memphis and Nashville
- I-75: Atlanta to Miami, with feels-like temps near 110°F throughout
- I-95: Jacksonville to Miami, and up through Georgia and South Carolina
Why Extreme Heat Is a Vehicle Story
Extreme heat is one of the most underappreciated dangers on the road. Tire blowouts spike during heat waves because underinflated tires heat up faster and fail catastrophically at highway speeds. Battery failures triple during extreme heat events. EVs lose 15 to 30 percent of range in temperatures above 100°F, and DC fast charging speeds are reduced to protect battery health.
The most serious hazard is heatstroke in vehicles. A car’s interior can climb from 90°F to 140°F in about 20 minutes, even with windows cracked. Never leave children, pets, or vulnerable adults in a parked vehicle in these conditions. Since 1998, more than 1,000 children have died from vehicular heatstroke in the US.
What Drivers Should Do
Check tire pressure in the morning before pavement heats up. Carry extra water, sunscreen and a first-aid kit. If your battery is more than three years old, consider having it tested before a long drive. Plan long-distance trips for early morning or evening. If your vehicle isn’t ready for a sudden bake in triple-digit heat, Autoblog’s guide to summer car readiness covers everything from coolant to cabin ventilation.
For real-time heat alerts and forecast updates, check the National Weather Service heat page and monitor local NWS office bulletins for your region.