Early Southwest heat is latest in parade of weather extremes as Earth
warms
[March 20, 2026]
By SETH BORENSTEIN
WASHINGTON (AP) — The dangerous heat wave shattering March records all
over the U.S. Southwest is more than just another extreme weather blip.
It’s the latest next-level weather wildness that is occurring ever more
frequently as Earth’s warming builds.
Experts said unprecedented and deadly weather extremes that sometimes
strike at abnormal times and in unusual places are putting more people
in danger. For example, the Southwest is used to coping with deadly
heat, but not months ahead of schedule, including a 110-degree
Fahrenheit (43.3 Celsius) reading in the Arizona desert on Thursday that
smashed the highest March temperature recorded in the U.S.
On Thursday, sites in Arizona and southern California had preliminary
readings of 109 F (about 43 C), which would be the hottest March day on
record for the United States.
“This is what climate change looks like in real time: extremes pushing
beyond the bounds we once thought possible,” said University of Victoria
climate scientist Andrew Weaver. “What used to be unprecedented events
are now recurring features of a warming world.”
March's heat would have been virtually impossible without human-caused
climate change, according to a report Friday by World Weather
Attribution, an international group of scientists who study the causes
of extreme weather events.
More than a dozen scientists, meteorologists and disaster experts
queried by The Associated Press put the March heat wave in a kind of
ultra-extreme classification with such events as the 2021 Pacific
Northwest heat wave, the 2022 Pakistan floods and killer hurricanes
Helene, Harvey and Sandy.
The area of the U.S. being hit by extreme weather in the past five years
has doubled from 20 years ago, according to the National Oceanic and
Atmospheric Administration's Climate Extremes Index, which includes
various types of wild weather, such as heat and cold waves, downpours
and drought.
The United States is breaking 77% more hot weather records now than in
the 1970s and 19% more than the 2010s, according to an AP analysis of
NOAA records. In the United States, the number and average cost of
inflation-adjusted billion-dollar weather disasters in the last couple
years is twice as high as just 10 years ago and nearly four times higher
than 30 years ago, according to records kept by NOAA and Climate
Central, a nonprofit group of scientists and communicators who research
and report on climate change.
Trying to keep up with extremes and failing
"It’s really hard to even keep up with how extreme our extremes are
becoming," said Climate Central Chief Meteorologist Bernadette Woods
Placky. “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.”
For government officials who have to deal with disaster it's been a huge
problem.
Craig Fugate, who directed the Federal Emergency Management Agency until
2017, said he saw extremes increasing.
“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," Fugate said
via email.
He added: “We built communities on about 100 years of past weather and
assumed that was a good guide going forward. That assumption is starting
to break. And the clearest signal isn’t the science debate. It’s
insurers walking away.”
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A sign warns hikers of trail closures due to extreme heat at
Camelback Mountain on Thursday, March 19, 2026, in Phoenix. (AP
Photo/Rebecca Noble)
‘Virtually impossible’ without climate change
Climate scientists at World Weather Attribution did a flash analysis
— which is not peer-reviewed yet — of whether climate change was a
factor in this Southwest heat wave. They compared this week's
expected temperatures to what's been observed in the area in March
since 1900 and computer models of a world with climate change. They
found that “events as warm as in March 2026 would have been
virtually impossible without human-induced climate change."
That warming, from the burning of coal, oil and natural gas, added
between 4.7 degrees to 7.2 degrees F (2.6 to 4 degrees C) to the
temperatures being felt, the report found.
“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,” said
report co-author Clair Barnes, an Imperial College of London
attribution scientist.
Examples abound of high heat and extreme weather
The Southwest heat wave is solidly in the category of “giant
events,” with temperatures up to 30 degrees Fahrenheit (16.7 degrees
Celsius) above normal, said Stanford University climate scientist
Chris Field.
He listed five others in the last six years: a 2020 Siberia heat
wave, the 2021 Pacific Northwest heat wave that had British Columbia
warmer than Death Valley, the summer of 2022 in North America, China
and Europe, a 2023 western Mediterranean heat wave and a 2023 South
Asian heat wave with high humidity.
And that doesn't include the East Antarctica heat wave of 2022 when
temperatures were 81 degrees (45 degrees Celsius) warmer than
normal. That's the biggest anomaly recorded, said weather historian
Chris Burt, author of the book “Extreme Weather.”
Worsening wild weather influenced by climate change isn't just
super-hot days, but includes deadly hurricanes, droughts and
downpours, scientists told AP.
Devastating floods hit West Africa in 2022 and again in 2024. Iran
is in the midst of a six-year drought. And the deadly Typhoon Haiyan
hitting the Philippines in 2013 shocked the world.
Superstorm Sandy, which in 2012 flooded New York City and neighbors,
had tropical storm-force winds that covered an area nearly one-fifth
the area of the contiguous United States. It spawned 12-foot seas
over 1.4 million square miles, about half the size of the U.S., with
energy equivalent to five Hiroshima-sized atomic bombs, said Yale
Climate Connections meteorologist Jeff Masters.
And don't forget wildfires that are worsened by heat and drought, so
recent extremes should include 2025's Palisades and Eaton wildfires,
which were the costliest weather disaster in the United States last
year, said Climate Central meteorologist and economist Adam Smith.
"This is due to climate change, that we see more extreme events, and
more intense ones and have so many records being broken,” said
Friederike Otto, an Imperial College of London climate scientist who
coordinates World Weather Attribution
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