Southwest Shatters March Heat Records as Climate Change Fuels Extremes

Experts warn that unprecedented and deadly weather events are becoming more common due to global warming.

Mar. 21, 2026 at 1:03am

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A dangerous heat wave has shattered March temperature records across the U.S. Southwest, with experts saying this is the latest example of the growing frequency of extreme weather events driven by climate change. Temperatures reached up to 30 degrees Fahrenheit above normal, with several communities hitting 112°F. Scientists say this heat wave would have been "virtually impossible" without human-caused global warming, which has added 4.7-7.2°F to the temperatures.

Why it matters

The Southwest is used to dealing with deadly heat, but not months ahead of the typical summer season. These types of unprecedented and extreme weather events are putting more people in danger as the climate continues to change. Experts warn that the U.S. is seeing a doubling of the area affected by extreme weather over the past 20 years, with the country breaking 77% more hot weather records now than in the 1970s.

The details

The heat wave saw temperatures spike to 112°F in two Arizona communities and two Southern California locations, all within about 50 miles of each other. Scientists say this level of heat in March would have been "virtually impossible" without the influence of human-caused climate change, which has added between 4.7-7.2°F to the temperatures. The extreme heat is part of a broader trend of worsening weather disasters, including devastating floods, droughts, and hurricanes, that are being fueled by global warming.

  • On Friday, March 21, 2026, temperatures reached 112°F in several Southwest communities.

The players

Andrew Weaver

A climate scientist at the University of Victoria.

Bernadette Woods Placky

The Chief Meteorologist at Climate Central, a nonprofit group of scientists and communicators who research and report on climate change.

Craig Fugate

The former director of the Federal Emergency Management Agency until 2017, who witnessed the increasing frequency of extreme weather events.

Clair Barnes

An attribution scientist at Imperial College of London who co-authored a report on the role of climate change in the Southwest heat wave.

Chris Field

A climate scientist at Stanford University who categorized the Southwest heat wave as a "giant event" in a list of other extreme weather incidents in recent years.

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What they’re saying

“This is what climate change looks like in real time: extremes pushing beyond the bounds we once thought possible.”

— Andrew Weaver, Climate Scientist

“It's really hard to even keep up with how extreme our extremes are becoming. It's changing our risk, it's change our relationship with weather, it's putting more people in risky situations and at times we're not used to. So yes, we are pushing extremes to new levels across all different types of weather.”

— Bernadette Woods Placky, Chief Meteorologist

“We were operating outside the historical playbook more and more. Flood maps, surge models, heat records — events kept showing up outside the envelope we built systems around. That's just what we saw.”

— Craig Fugate, Former FEMA Director

“What we can very confidently say is that human-caused warming has increased the temperatures that we're seeing as a result of this heat dome, and it's going to be pushing those temperatures from what would have been very uncomfortable into potentially dangerous.”

— Clair Barnes, Attribution Scientist

“This is due to climate change, that we see more extreme events, and more intense ones and have so many records being broken.”

— Friederike Otto, Climate Scientist

What’s next

The World Weather Attribution report on the role of climate change in the Southwest heat wave is expected to be peer-reviewed and published in the coming weeks.

The takeaway

The extreme heat wave in the Southwest is the latest example of how climate change is fueling unprecedented and deadly weather events, putting more people at risk. Experts warn that the frequency and intensity of these extremes will only continue to worsen unless significant action is taken to reduce greenhouse gas emissions and mitigate the impacts of global warming.