Southwest Scorched by Rare March Heat Wave

Temperatures soar 15-30 degrees above average, raising wildfire concerns

Mar. 18, 2026 at 5:38am

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A powerful high-pressure system has brought an intense heat wave to the Southwest, with temperatures well into the 90s and even reaching 100 degrees in some areas. Meteorologists have issued extreme heat warnings, cautioning residents to stay indoors, hydrate, and avoid outdoor activities during the hottest parts of the day. The record-breaking heat, combined with dry conditions and high winds, has also raised the risk of wildfires across the region.

Why it matters

This early-season heat wave is highly unusual and concerning, as it comes amid ongoing drought conditions and a trend of more frequent record-high temperatures in recent years. Experts attribute the extreme weather to a combination of climate change and a La Niña weather pattern, underscoring the growing challenges posed by a warming planet.

The details

The heat wave is expected to last through the weekend, with daily highs in Los Angeles, Phoenix, and Las Vegas potentially breaking historic records by nearly 10 degrees. Meteorologists have warned of a high risk of heat-related illnesses and have advised residents to limit time outdoors, use air conditioning, and stay hydrated. In Colorado, the heat and dry conditions have also triggered red flag fire warnings, prompting officials to urge caution with any activities that could spark a blaze.

  • The heat wave is expected to last from Wednesday, March 18 through Sunday, March 22.
  • On Tuesday, March 17, the National Weather Service issued extreme heat warnings for the southern half of Arizona.
  • In the Bay Area, the first March heat advisory in 20 years was issued, with temperatures expected to reach the 80s and 90s.

The players

Roger Gass

A meteorologist at the Monterey National Weather Service office, which oversees the Bay Area.

Brian Planz

A meteorologist at the Las Vegas National Weather Service office.

Kenley Bonner

A meteorologist at the Denver/Boulder National Weather Service office.

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What they’re saying

“We have a very strong high pressure building overhead. It's currently just off the Central Coast, and it's going to build inland through Wednesday and strengthen.”

— Roger Gass, Meteorologist

“It's going to bring well-above normal temperatures to the area, most likely record-setting heat and record highs for [Las] Vegas later in the week.”

— Brian Planz, Meteorologist

“No precipitation is in the forecast, and we will have critical fire weather conditions.”

— Kenley Bonner, Meteorologist

What’s next

Meteorologists will continue to monitor the situation and provide updates on the heat wave and any potential wildfires. Residents in the affected areas are advised to stay vigilant and follow the guidance of local authorities.

The takeaway

This early-season heat wave is a stark reminder of the growing impacts of climate change, as extreme weather events become more frequent and severe. Experts warn that the combination of high temperatures, dry conditions, and high winds poses a serious threat to public safety and the environment, underscoring the need for proactive measures to address the challenges posed by a warming planet.