Nature
PUBLISHED
The contiguous US has just gone through the hottest September since records began in the 19th century, smashing the previous record with temperatures 2.5°C (4.6°F) above the 20th-century average.
An unusually warm September
Newly released data from NOAA shows that September 2026 across the contiguous US had an average temperature of 20.7°C (69.4°F), beating the previous record set in 1998 of 20.52°C (68.95°F).
Unusually warm weather has been seen particularly across the interior US, and especially the South Central region extending through to the East Coast.
Meanwhile, small parts of northern California and the Pacific Northwest actually recorded below-average temperatures. Regardless, the zoomed-out picture is one of exceptional warmth.
Shhh, don't mention climate change
The new record is another sign that the impacts of human-driven climate change are already being felt, although rather tellingly the NOAA statement makes no mention of it.
Under the Trump Administration, NOAA has continually shied away from linking warming weather to climate change and greenhouse gas emissions.
Faced with heavy budget cuts under Trump’s proposed 2027 Budget, there were even suggestions that the agency should “no longer support climate research grants.”
“With that statement, the administration signals its intent to have NOAA, arguably the world’s leading oceanic and atmospheric governmental organization, completely abandon climate science,” Alan Gerard, meteorologist and former NOAA official, wrote on his Substack in July.
El Niño is another factor
The latter half of 2026 also experienced the growth of a super El Niño event, a momentous weather phenomenon that’s known to push up global average temperatures.
As a result of both climate change and the El Niño, some scientists are already hedging their bets that 2026 could become the warmest year on record. The previous record was 2024, followed by 2023 and 2025, so that forecast would fit the pattern neatly.
It looks as if temperatures will remain unseasonably warm as fall settles in through October. NOAA is forecasting that this month will also see elevated temperatures across the West Coast, the northern Plains, the Gulf Coast region, and southeastern Alaska. You can also expect it to be exceptionally rainy across much of the south.
Across the Atlantic and Down Under
Elsewhere on planet Earth, it was a similar picture.
The Australian Bureau of Meteorology reported the second-hottest September on record, with temperatures 2.71 °C (4.8 °F) above average, while the Met Office said the UK saw the joint-fourth warmest September since records began in 1884.
The UK’s meteorologists, however, were less coy about drawing a link between the warm weather and climate change.
“While the month itself was unexceptional overall, when putting it into the context of the warm year we’ve had so far, this fits with the general pattern that we’re seeing of more frequent above-average temperatures in the UK as our climate continues to change,” Mike Kendon, Climate Information Scientist at the Met Office, said in a statement.
