States across the US south-west are experiencing a historic March heatwave, with temperatures 25-35°F above normal. The National Weather Service (NWS) has issued heat warnings for California, Nevada and Arizona, where numerous daily and monthly records have been broken.
In California, Palm Springs is expected to reach 108°F on Thursday, while North Shore tied the highest March temperature ever recorded in the US at 108°F. Downtown Los Angeles hit 94°F, beating its previous daily high for 18 March of 87°F set in 1997. The NWS Los Angeles warned of “extremely rare heat for March” and a high risk of heat illness.
Arizona's Phoenix set a record-high overnight low for 19 March of 69°F, with daytime highs expected to reach 105°F. The NWS noted that the average first 105°F day normally occurs on 22 May, and the last time Phoenix saw triple-digit temperatures in March was almost 40 years ago. Records are expected to be broken each day through Sunday.
In Nevada, Reno and Las Vegas have also seen record-setting warmth. The NWS Las Vegas stated that “daily and monthly temperature records continue to be rewritten as this historic March heatwave persists into next week.” Temperatures are forecast to cool next week, with Los Angeles dropping to about 80°F.
National parks in the region have urged visitors to check forecasts and take precautions. The Grand Canyon is under an extreme heat warning, with temperatures possibly reaching 104°F. Hiking trails at Lake Mead national recreation area have been closed due to the heat.
