The average maximum temperature for March was especially high at 11.4 F (6.3 C) above the 20th century average and was almost a degree warmer than the average daytime high for April, NOAA said.
Six of the nation’s top 10 most abnormally hot months have been in the last 10 years. This February, which was 6.57 F (3.65 C) above 20th century normal, was the tenth highest above normal.
“What we experienced in March across the United States was unprecedented,” said Shel Winkley, a meteorologist with Climate Central, a nonprofit science research group.
April 2025 to March 2026 was the warmest 12-month period on record in the continental United States, according to NOAA.
On March 20 and 21, about one-third of the nation felt unseasonable heat that would have been virtually impossible without human-caused climate change, Climate Central calculated.
More than 19,800 daily temperature records were broken for heat across the country, according to meteorologist Guy Walton, who analyzes NOAA data. More than 2,000 places set monthly records for heat — harder to break than daily records — Walton calculated. That’s more March heat records set just last month than in entire decades in the past.
All those broken records “tells us that climate change is kicking our butts,” said meteorologist Jeff Masters of Yale Climate Connections.
“January through March period was the driest on record for the contiguous U.S. So not only was it hot, it was record dry as well,” Masters said. “And that’s a bad combination for water availability, for agriculture, for river levels, for navigation.”
An El Niño releases heat stored in the upper ocean into the air, which causes global temperatures to rise, but with a few months lag time, said Northern Illinois University meteorology professor Victor Gensini.
“A strong El Niño could plausibly push global temperatures to new record levels in late 2026 and into 2027,” Gensini said.
“Global warming is supercharging El Niños and the atmospheric warming they drive,” said University of Michigan environment dean and climate scientist Jonathan Overpeck. “We saw this in 2016 and more recently in 2023. We’re likely to see another jump in global temperatures if a strong El Niño develops later this year as being predicted.”
El Niños tend to tamp down hurricane activity in the Atlantic, but ramp it up in the Pacific and could help ease the southwestern drought, Masters said.
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