In mid-September 2026, a heat dome caused extreme temperatures across the south-central U.S., despite the approaching end of summer. On September 15, temperatures soared, exceeding 40°C (104°F) in some areas, prompting advisories for over 41 million Americans.
Maps showed the highest temperatures extending across states like Texas, Oklahoma, Arkansas, Missouri, and Tennessee, where cities like Dallas (101°F), Memphis (99°F), and Nashville (100°F) recorded significant highs—Nashville even broke a record set in 1927.
This heat wave followed an exceptionally warm summer, marking the hottest June through August in 132 years. Meteorologists attributed these extreme conditions to a heat dome—a phenomenon where high-pressure systems trap hot air near the surface, limiting cooling effects from convection and inhibiting cloud formation.
