YUMA DESERT, ARIZONA — A site just outside Martinez Lake in Arizona's Yuma Desert recorded 43C (110F) on Thursday, setting a new U.S. record for the highest March temperature. The temperature surpassed the previous national March record of 42C (108F), set in Rio Grande City, Texas, in 1964.
Records for unusually early high temperatures were broken in California, Arizona, and Nevada. Phoenix recorded 40C (105F) on Thursday, setting its hottest March day on record after breaking its previous record of 39C (102F) just one day earlier on Wednesday.
Las Vegas reached 35C (95F) on Thursday, surpassing its previous March temperature record of 34C (94F) set on Wednesday. On 18 March, a town near North Shore, California recorded 42C (108F), matching the previous U.S. March temperature record.
A strong, slow-moving high-pressure system, often called a heat dome, trapped hot air over the region and pushed temperatures 20–30F above normal. In Las Vegas, the average first 105F day of the year typically occurs at the end of May.
Heatwaves have become more frequent, more intense, and last longer due to human-induced climate change. Since the industrial era began, the global average temperature has increased by about 1.1C. Global temperatures are projected to continue rising unless governments worldwide make steep cuts to emissions.