Science1 publisher2 min readPublished
A typical recent autumn would make 2026 the hottest U.S. year on record
Contiguous U.S. temperatures averaged 57.98 degrees F from January to August 2026, the hottest such stretch since records began in 1895, NOAA data show. Only a cooler-than-normal fall would keep 2026 from an annual record, Zeke Hausfather says.
The Scientist · Science desk
What happened
- The 2026 figure topped the previous January-August record of 57.90 degrees F, set in 2012, by 0.08 degrees, according to NOAA.
- Climatologist Zeke Hausfather calculates that a September-December average above about 50.5 degrees F would beat 2024's annual record of 55.48 degrees.
- Hausfather puts the odds that 2026 becomes the hottest year on record for the contiguous U.S. at about 80 percent.
- Climate Central's Zachary Labe pointed out that at this point in 2024, the eventual record year ranked only second warmest.
Compiled by The ScientistSomething wrong?How this is made
Why it matters
- decision Heat thresholds pegged to the 20th-century average sit about 2.6 degrees F below a typical recent autumn. The choice of reference period decides how often they trip.
- contradiction Hausfather's 80 percent estimate and NOAA's refusal to call a record mean the ranking stays a forecast until year-end data arrive. Anyone citing 2026 as the hottest year is ahead of the agency.
- exposure A second- or third-place finish would leave the exposure in place: Cobb argues that heat waves and extreme rainfall threaten infrastructure and health at the warmth already recorded.
On its own, beating a 2012 mark by eight hundredths of a degree is a thin record [3]. That eight-month record had stood for 14 years [3]. A second figure, about baselines, comes from Zeke Hausfather, a climatologist and a lead author of the IPCC's Seventh Assessment Report [4].
His 50.5-degree autumn threshold passes a rough check [5]. Weight the eight warm months and the four cooler ones equally and (8 x 57.98 + 4 x 50.5) / 12 comes to about 55.49 degrees F, against 2024's annual record of 55.48 [2]. Months differ in length, so this shows the threshold is consistent with the two averages. It does not reproduce his method.
As an anomaly, this fall needs to run 2.2 degrees F above the 20th-century average, Hausfather said. The final four months of the past ten years averaged about 2.6 degrees above it [7]. That leaves roughly 0.4 degrees of room [1]. "That is a warm autumn, but not an unusual one anymore," he said [6].
An ordinary autumn of the past decade clears the 20th-century average by more than the 2.2 degrees a record requires [7][1].
NOAA would not commit. A NOAA spokesperson shared an early look at September and the agency's outlook for above-normal temperatures across much of the continental U.S. from October through December [10]. Citing NOAA physical scientist Russell Vose, the spokesperson said neither one absolutely predicts a record year [10]. Scientific American reports that data suggest September was anomalously warm [9].
Kim Cobb, a climate scientist at Brown University, called a record "more than likely" [13]. Zachary Labe of Climate Central said weather forecasting is complex and variable enough to make the call tricky [17]. "Average temperatures across the country continue to reach new record levels, which is consistent with the long-term warming driven by human-caused climate change," Labe said [12].
What to watch
- NOAA's year-end tally, and whether the fall clears the 2.2-degree anomaly Hausfather says a record requires.
- The super El Nino building in the Pacific; Cobb says current projections point to record-shattering global temperatures in 2027.