Rare March heat wave grips Western US cities

San Francisco nears 90 degrees as Phoenix, Las Vegas also see record-breaking temperatures

Mar. 18, 2026 at 1:04am

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A prolonged and unusual March heat wave is gripping cities across the Western United States, pushing temperatures in San Francisco close to 90 degrees and setting records across the region. The heat wave is in stark contrast to the Midwest and eastern half of the country, which are digging out after powerful snow storms.

Why it matters

The rare March heat wave is causing concern in Western cities, many of which are not equipped to handle such high temperatures this early in the year. The heat is putting a strain on water resources and prompting warnings about the risks of dehydration and heat-related illnesses, especially for vulnerable populations.

The details

San Francisco, better known for its chilly summers and fog, is experiencing its hottest March in at least two decades, with temperatures flirting with 90 degrees. Other cities like Phoenix and Las Vegas are also seeing record-breaking heat, with Phoenix expected to top 100 degrees this week - something it usually doesn't see until early May. The heat wave is in stark contrast to the Midwest and eastern half of the country, which have been hit by powerful snow storms.

  • On Tuesday, temperatures in San Francisco looked to tie the record high for March.
  • Las Vegas could see its hottest March stretch ever recorded this weekend.
  • Denver hasn't seen three consecutive March days above 80 degrees Fahrenheit since 1907, but it could happen again this week.

The players

Roger Gass

A meteorologist with the National Weather Service in the Bay Area.

Brian Planz

A meteorologist at the National Weather Service forecast office in Las Vegas.

Shonnie Cline

A spokesperson for Aurora Water, which provides water to 400,000 people in suburban Denver.

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What they’re saying

“It feels like summer already in March. That's crazy, but I love it.”

— Justyce Roliz, dog walker

“We have our fans going, our windows open, but we try to be outside as much as we can.”

— Jessica Ling, San Francisco resident

“If people are visiting Vegas this weekend, they just need to prepare for the heat, make sure they're hydrating. This is going to be unusual for this time of year.”

— Brian Planz, meteorologist

“For me, this is the trip of a lifetime. I've never been to the USA before and I may never get here again.”

— Mark Reeves

“The sooner you wake it up, it's not necessarily better.”

— Shonnie Cline, spokesperson for Aurora Water

What’s next

Water providers in the Denver area have already enacted or are considering limits on the number of days people can water their lawns, urging people not to turn on their sprinklers this month to avoid potential damage from freezing temperatures.

The takeaway

This rare March heat wave in the Western US highlights the growing challenges posed by climate change, with cities that are typically cooler this time of year now grappling with record-breaking temperatures and the strain on resources like water supply. It underscores the need for communities to prepare for and adapt to more extreme weather patterns in the years ahead.