Southwest U.S. Heat Wave

North Shore, California, reached 108°F on March 18, 2026, tying the highest March temperature ever recorded in the U.S. (set in Rio Grande City, Texas, in 1954), while nearby Thermal was forecast to reach 110°F and potentially break the record. The heat wave has produced numerous city records — Phoenix hit an earliest-ever 101°F in March, Las Vegas reached 99°F, downtown Los Angeles 94°F and Palm Springs 104°F — left more than 41 million people under heat alerts, and was called “one of the most significant March heat waves in recorded history” by the NWS.