California Town Ties Nation’s Hottest March Temperature as Early Heat Wave Shatters Records

A record-setting March scorcher

NORTH SHORE, Calif. — By midafternoon Wednesday, the swings at North Shore’s small playground sat empty, too hot for children to touch. Heat shimmered over the dirt lots and the receding shoreline of the Salton Sea. At a roadside market off Highway 111, a digital thermometer blinked 108 degrees.

It was March 18.

That reading, from an official weather station in this unincorporated Riverside County community, tied the highest March temperature ever recorded in the United States. The mark was first reached in Rio Grande City, Texas, in 1954 and had stood alone in the record books for more than 70 years.

The searing afternoon was part of a rare, early-season heat wave that has pushed temperatures 20 to 30 degrees above normal across the interior West, shattering March records from Southern California to Arizona and Nevada. Meteorologists and climate scientists say the event illustrates how extreme heat is arriving earlier in the year in the already-warming Southwest, with particular consequences for low-income and outdoor-worker communities like North Shore.

“This is one of the most significant March heat waves in recorded history for this region,” said Bryan Lewis, a meteorologist with the National Weather Service. “We’ve broken so many records yesterday and even today we’ve broken quite a few so far.”

Records from California to Nevada

On Wednesday, Phoenix reached 101 degrees, its earliest triple-digit temperature on record. The National Weather Service said the previous earliest 100-degree day there was March 26, 1988, and that was the only other time the city had ever hit 100 in March.

Elsewhere across the West:

• Las Vegas climbed to 99 degrees, breaking its all-time March record of 93 set in 2022.
• Downtown Los Angeles hit 94, topping the previous daily record of 87 set in 1997.
• Palm Springs reached 104, tying its hottest March day, first recorded in 1966.

Forecasters warned the heat would linger into the weekend, with nearby Thermal, California, expected to reach or exceed 110 degrees — a level more typical of late June than mid-March.

What’s driving the heat

The pattern is being driven by a strong, stationary ridge of high pressure — often referred to as a “heat dome” — parked over the western United States. The system promotes clear skies and sinking air that compresses and warms, allowing temperatures to spike far above seasonal norms.

While the Southwest baked, a powerful late-season storm brought blizzard conditions and bitter cold to parts of the Midwest and Northeast — a contrast some scientists describe as “weather whiplash” in a warming climate.

A hard hit for farmworker communities

In North Shore, a community of about 3,500 people on the northeast edge of the Salton Sea, the record felt less abstract.

Most residents are Latino, many from farmworker families who labor in the date groves, citrus orchards and vegetable fields of the eastern Coachella Valley. Census data show more than 95% of residents identify as Hispanic or Latino, the median age is around 28, and poverty rates are significantly higher than the state average.

On hot days, workers often remain in the fields until evening.

“When it gets like this, people still have to go to work,” said a local organizer who works with farmworker families and asked not to be named because she was not authorized by her nonprofit to speak on the record. “A lot of them don’t have air conditioning at home or can’t afford to run it all day. They’re tired from the heat, and then they go back to trailers or small houses that stay hot at night.”

Health experts say early-season heat waves can be especially dangerous because people’s bodies have not yet adjusted to high temperatures and because public-health agencies often gear their heat-response plans to summer months. Air-conditioning systems may not have been serviced or turned on, and formal cooling centers are less likely to be open.

“The first serious hot spell of the year is when we tend to see a spike in heat illness,” said a public health researcher who has studied heat impacts in the Southwest. “People are caught off guard.”

Salton Sea dust and compounding health risks

Around the Salton Sea, those risks are layered atop long-running environmental problems. The inland lake, sustained for decades by agricultural runoff, has steadily shrunk as inflows have declined under Colorado River water agreements and ongoing drought. As the shoreline recedes, it exposes a powder-fine lakebed that can send alkaline dust and farm-chemical residues into surrounding communities when winds rise.

Residents and health advocates have long reported high rates of asthma and other respiratory symptoms in North Shore and nearby communities such as Mecca, Oasis and Thermal.

“People here are dealing with the dust from the sea, with contaminated water, with a lack of clinics, and now the heat is getting worse,” said Maria Pozar, a North Shore resident and community advocate, in an earlier interview about conditions in the eastern Coachella Valley. She said she believes county leaders have historically neglected the area, remarking that officials “only know the Eastern Coachella Valley exists because it’s on a map.”

Public-health researchers have identified these Salton Sea-adjacent towns as environmental justice hotspots: largely Latino and Indigenous communities, many living in poverty, with elevated exposure to air pollution and limited access to medical care. Extreme heat compounds those vulnerabilities, particularly for children, older adults and people with existing heart or lung conditions.

Why 108 matters nationally

The national significance of North Shore’s 108-degree reading lies not just in its location but in the record it matched.

Rio Grande City, a city in Starr County along the Texas-Mexico border, hit 108 degrees on March 14, 1902, and again on March 31, 1954. Weather historians have long cited those episodes as the highest March temperatures ever recorded in the United States. Rio Grande City, like North Shore, sits in a hot, semi-arid region and has a large Latino population.

For another community to reach that mark — and for it to happen in mid-March rather than at the very end of the month — underscores how unusual this year’s heat is, climatologists say.

Long-term data show the American Southwest warming faster than the global average, with more frequent and intense heat waves and a trend toward hotter nights and longer warm seasons. Federal climate assessments have warned that extreme heat days are increasing in low-elevation deserts such as the Coachella and Imperial valleys and the lower Colorado River region.

Snow drought, water stress and wildfire concerns

At the same time, the West is in the grip of what federal agencies have called a record snow drought. As of mid-March, snow-monitoring stations showed Arizona’s statewide snow water equivalent at about one-quarter of its typical seasonal peak, the lowest on record. Snowpack in parts of Colorado and Utah, which feed the Colorado River, is also well below normal.

Less snow combined with earlier, hotter spring weather can mean reduced runoff into reservoirs and drier vegetation heading into summer, raising concerns about water supplies and wildfire risk.

“Hot, dry conditions in March dry out grasses and other fine fuels much earlier than usual,” said an official involved in Western wildfire monitoring. “That can lengthen the fire season and increase the window of time when large, fast-moving fires are possible.”

What communities are asking for

For communities like North Shore, broad regional trends translate into immediate questions about daily life: how to keep homes cool without soaring power bills, how to protect outdoor workers, how to safeguard children with asthma when hot, dusty winds blow off the lakebed.

Local officials in Riverside County routinely issue heat advisories and have supported Salton Sea restoration projects focused on dust suppression and habitat. Community groups argue more is needed, including additional clinics, shaded public spaces, reliable transit to cooling centers and stronger workplace protections for agricultural laborers.

On Wednesday evening, as the sun slid behind the Santa Rosa Mountains, temperatures in North Shore eased but remained well above a typical March night. The Salton Sea’s surface glowed pink in the fading light, its ragged shoreline a reminder of the region’s ongoing water and environmental challenges.

For now, the 108-degree reading will be entered as a line in a federal climate database, a tie atop the list of the nation’s hottest March days. For residents here, it was another signal that what used to be summer heat is arriving earlier and staying longer.

How often that number — or higher — appears in future March forecasts may help define what living in the deserts of the Southwest will mean in the decades ahead.