Rare September Heat Dome Shatters Records in U.S.
A rare heat dome in mid-September 2026 has brought record-breaking temperatures across the south-central United States. On September 15, cities like Dallas, Memphis, and Nashville experienced extreme heat, with temperatures reaching 101°F (38.3°C), 99°F (37.2°C), and 100°F (37.8°C), respectively. These readings were significantly above normal for the date, with Nashville breaking a daily record that had stood since 1927. The heat dome, characterized by high atmospheric pressure, trapped hot air near the surface, leading to persistent high temperatures and limited cloud cover. NASA maps showed the darkest red areas over Texas, Oklahoma, Arkansas, Missouri, and Tennessee. This event followed the warmest June-through-August period ever recorded for the contiguous United States, according to NOAA.