September 2026 was the second-hottest September on record for the planet, NOAA's National Centers for Environmental Information reported Friday. Only September 2023 was warmer. NASA and Europe's Copernicus climate service agree, Yale Climate Connections reported.

Record heat covered 16.7% of Earth's land and ocean surface. That is the largest share for any month since records began in 1951, beating 14.2% in May 2024. No place set a cold record. The oceans had their warmest September on record.

At home, it was the hottest September ever for the Lower 48 states, according to a separate NOAA report. It broke the old mark from 1998, ABC News reported, and records go back to 1895.

The heat was worst at night. The average low across the 48 states was 57.47 degrees, more than 1.2 degrees above the old record from 2019, Yale Climate Connections said. About 80 million people had their warmest September nights on record, ABC reported. Warm nights matter because bodies, homes and crops cannot cool off.

The central states baked. Oklahoma averaged 82.8 degrees, smashing a 1931 Dust Bowl record. Kansas, Missouri, Arkansas and Illinois also set records. The outlets give different counts, though. ABC lists eight states with their warmest September. Yale Climate Connections, citing a NOAA map, says 13 did.

It was the 20th straight month of above-average heat for the Lower 48. Four months this year have set records: March, July, August and September. The year so far is the warmest on record for the U.S.

Rain was mixed. Arizona and New Mexico got soaked by storms fed by Pacific hurricanes. But about 55% of the Lower 48 was in drought, ABC reported.

A record-strong El Niño is building in the Pacific. Scientists expect it to push 2027 even higher.

What we know: September set a U.S. heat record and ranked second worldwide.
What we don't: Whether 2026 will end as the hottest year on record.