Historic March Heatwave Shatters Records Across US Southwest
A historic March heatwave has shattered high-temperature records across the US Southwest, with blistering temperatures in California, Nevada, and Arizona reaching 25-35°F above normal levels. This extreme weather event, occurring at the tail end of winter, has prompted widespread heat alerts, closures, and warnings of continued hot days ahead.
Record-Breaking Temperatures and Widespread Alerts
On Thursday, California, Nevada, and Arizona were all under heat warnings as temperatures soared to unprecedented levels for March. The National Weather Service (NWS) described the conditions in the Los Angeles area as "extremely rare heat for March", highlighting a high risk for heat illness among residents. Palm Springs, located approximately 100 miles east of Los Angeles, was expected to reach a scorching 108°F, with heat alerts remaining in effect through Sunday.
The NWS Los Angeles heat advisory emphasized that many daily records will be shattered, with temperatures 25-35 degrees above normal. This follows a day when a tiny desert community in southern California tied the highest March temperature ever recorded in the US at 108°F, matching a record first set in Rio Grande City, Texas, in 1954.
Specific Regional Impacts and Forecasts
In Arizona, Phoenix set a record-high overnight low temperature for March 19th at 69°F, with daytime highs expected to top out around 105°F and potentially even hotter on Friday. The NWS Phoenix office noted that daily records will be broken each day through Sunday, with peaks anticipated for Friday. For perspective, the average first 105°F day in Phoenix typically occurs on May 22nd, making this heatwave exceptionally early and severe.
Other areas experienced similar extremes:
- Cathedral City, near Palm Springs, reached 108°F on Thursday.
- Thermal, northeast of San Diego, was forecast to hit 110°F on Friday.
- Downtown Los Angeles reached 94°F, beating its previous daily high for March 18th set in 1997.
Several daily heat records were already broken on Tuesday across more than a dozen areas in Los Angeles, as reported by the NWS on social media.
Northern California and Nevada Also Affected
Though not as scorching as southern regions, the heatwave has extended to northern California, with San Francisco facing a moderate heat risk. In Nevada, Reno has experienced record-setting warmth, with temperatures expected to peak on Friday. Las Vegas already set a March record on Wednesday, with the NWS Las Vegas stating that "daily and monthly temperature records continue to be rewritten" as the historic heatwave persists into next week.
Public Safety Measures and Park Closures
In response to the extreme conditions, some western national parks have urged visitors to check forecasts before heading out. High temperatures at White Sands National Park in New Mexico could reach the mid-90s°F, while Grand Canyon National Park in Arizona was under an extreme heat warning, with temperatures possibly hitting 104°F in some areas.
Park officials have warned hikers to avoid strenuous activity during the hottest part of the day, typically from 10 a.m. to 4 p.m. Additionally, hiking trails at Lake Mead National Recreation Area were closed due to the heatwave, according to a notice from the National Park Service.
Temperatures are expected to cool next week, with Los Angeles dipping to around 80°F, providing some relief from the unprecedented March heat.
