Berkeley Earth puts 96% odds on 2026 as hottest year

A record-strength El Niño has made it very likely that 2026 will overtake 2024 as the hottest year on record. Berkeley Earth's latest monthly update, released Thursday, October 22, puts the chance at roughly 96%, up from about 93% a month earlier. Other agencies are more cautious. The US National Oceanic and Atmospheric Administration (NOAA) still expects 2026 to fall just short of the 2024 record and come a close second. The European Union's Copernicus Climate Change Service, using data through September, ranks 2026 as the second-hottest year so far.business-standard.com+2

A sharp turn in the forecast

The research nonprofit's outlook has changed fast. Its May update gave only about a 2.5% chance of a record year. In August, Berkeley Earth said the odds had jumped from 12% to 69% in a single month as an El Niño that began in June gained strength. The group now puts the only realistic alternative, a second-place finish, at about 4%. It also expects the 2026 annual average to land roughly 1.50 to 1.60 C above pre-industrial levels. The group warned that the forecast assumes the El Niño develops like other very strong events. An unusually early peak in October is the most likely way 2026 could miss the record.berkeleyearth.org+2

September 2026 was the second-warmest September since records began in 1850. The global average was 1.65 C above the 1850-1900 baseline, only 0.06 C behind September 2023. Fifty-three countries set national heat records, and Spain, Portugal and Italy saw unusual late-summer heat. "It is still quite hot, even if it's not quite that bananas," said Robert Rohde, Berkeley Earth's chief scientist, referring to 2023.business-standard.com+1

Record El Niño may peak in December

The September Niño 3.4 index, a standard measure of El Niño strength, reached about 2.9 C. That beat the 2.75 C recorded in 2015 and 1877, and daily readings had climbed to 3.4 C by early October. Forecast models released in October point to a peak of about 4 C, more likely in December than in November. NOAA's Climate Prediction Center expects a strong to very strong event to last through January–March 2027.berkeleyearth.org

"It may well be possible that this could be the strongest El Niño event in a thousand years," Berkeley Earth research scientist Zeke Hausfather told Bloomberg. Climate researchers are still debating that idea.bloomberg.com

Hotter still in 2027

El Niño is already worsening droughts and floods, which are pushing up food prices and fueling wildfires. Global temperatures respond to El Niño with a delay, so its warming effect is expected to keep building into 2027. Scientists are confident that 2027 will be even hotter than this year.business-standard.com+1