24 October 2026 — The year 2026 now has roughly a 96% chance of surpassing 2024 to become the warmest year on record, according to a monthly analysis released this week by the research nonprofit Berkeley Earth, after a powerful El Niño dramatically reversed the year's temperature outlook and pushed ocean heat to record levels in September.
Illustration: Global heat concentrated over the Pacific, as Berkeley Earth raises the odds of 2026 becoming the hottest year on record.
Berkeley Earth's September 2026 temperature update, reported by Bloomberg on 24 October 2026, puts the chance of a new annual record at about 96%, up from about 93% in its August update, with a second-place finish as the only plausible alternative at about 4%. The group estimates the 2026 annual average is all but certain to exceed 1.5 degrees Celsius above the 1850–1900 average, with a likely annual range of roughly 1.50–1.60 degrees Celsius.
The swing in the forecast is itself the story. At the start of 2026, Berkeley Earth gave the record only a 12% chance, and that figure fell further by late spring. Then the Pacific changed. The emergence of a record-breaking El Niño flipped the calculation within weeks, and by autumn the group's analysts were describing a record as the expected outcome rather than a long shot.
What Happened
Berkeley Earth's update draws on nine months of temperature data. September supplied much of the evidence: the month ranked as the second warmest September worldwide, behind only September 2023, according to reporting on the update, and ocean temperatures reached a record for September. One analysis of the Berkeley Earth data reported ocean temperatures 1.368 degrees Celsius above the 1850–1900 average for September, described as nominally the warmest month of any kind in the ocean record — a figure readers should treat as reported analysis of the dataset rather than a directly quoted Berkeley Earth headline, since different summaries emphasise different records.
Berkeley Earth research scientist Zeke Hausfather was quoted as saying it "may well be possible that this could be the strongest El Niño event in a thousand years," citing a topic climate researchers have recently debated. That phrasing matters: it is a possibility raised by researchers, not a settled measurement of a thousand-year record, and the update itself is careful to make its forecast conditional on the El Niño continuing to develop in a typical fashion, similar to other very strong events.
Not every tracker agrees. The United States National Oceanic and Atmospheric Administration (NOAA) forecasts that 2026 is still unlikely to supplant the 2024 record but will come a close second, according to Bloomberg's report. The European Union's Copernicus Climate Change Service, working from data through September, ranks 2026 as the second hottest year to date — a middle position between Berkeley Earth's bolder call and NOAA's caution. The disagreement is normal: different groups use different datasets and methods, and their estimates typically fall within a tenth of a degree of each other.
Illustration: A Pacific island shoreline under heat and storm clouds, as El Niño warming spreads from the ocean into the atmosphere.
Background
El Niño is a natural feature of global weather marked by occasional warming of the eastern tropical Pacific. It temporarily adds to human-caused global warming by pushing more ocean heat and moisture into the atmosphere for months at a time. The current pattern has been compared with previous historically strong El Niños in 1997–1998 and 2015–2016, which brought dryness to Indonesia and the Philippines and parts of the Americas, and wet conditions to the southern and western United States. The difference now, researchers note, is that the underlying ocean is warmer than in those earlier events, which can amplify the impacts.
China's National Climate Centre said in early October 2026 that a super El Niño had officially formed in September, after rapid warming from May to September met the criteria for the extreme event, according to Reuters. Sea surface temperatures across most of the equatorial Pacific in September were above average, with the centre of the warm waters in the eastern equatorial Pacific exceeding the average by 3 degrees Celsius, according to that centre's data. Its chief forecaster was reported as expecting surface temperatures in the central and eastern equatorial Pacific to keep rising in the next three months, peaking in late autumn and early winter.
The timing explains why the annual record matters beyond a single year. Because the global temperature response typically lags the peak in the central Pacific by several months, much of this event's warming influence is expected to carry into 2027. Bloomberg's report notes that scientists expect 2027 to be hotter still — a prospect that would make the current El Niño not just a record-year story, but the opening of a hotter multi-year stretch.
Why It Matters
A single annual record does not, by itself, prove a change in the long-term climate trend; individual years are noisy, and El Niño years are expected to run hot. What makes this forecast significant is the combination: a record-breaking natural event layered on top of a warming baseline, producing a year that was a long shot in January and is now the expected outcome in October. That reversal shows how quickly a strong El Niño can overwhelm the usual year-to-year variation, and why forecasters watch the Pacific so closely.
The human consequences are already visible in the pattern Berkeley Earth's analysis describes. A strong El Niño is already worsening droughts and floods that are pushing up food prices and fuelling wildfires, according to Bloomberg's report. Those impacts fall unevenly: the same event that brings rain to one region can bring drought to another, and the hottest year on record would arrive on top of existing heat, water and food pressures in many countries.
The forecast also carries a caveat that deserves as much attention as the headline number. Berkeley Earth itself notes that a large deviation from typical behaviour — such as an early peak in October — is the most likely scenario for avoiding record warmth. The 96% figure is therefore a conditional forecast, not a certainty, and it will be tested by the Pacific's behaviour in the final months of the year.
Illustration: Cracked earth and wildfire smoke under a hazy sky, showing the drought and fire risks that accompany strong El Niño heat.
What Happens Next
The next data points will come month by month. October, November and December temperatures will determine whether Berkeley Earth's 96% call or NOAA's more cautious second-place forecast proves correct, and whether the El Niño peaks when forecasters expect. The annual ranking itself will not be final until early 2027, when complete-year datasets from Berkeley Earth, NOAA, Copernicus and other groups are compared.
Beyond the ranking, attention will turn to 2027. If the El Niño's warming influence carries into next year as Berkeley Earth expects, 2027 could challenge the new record almost immediately — a reminder that "hottest year on record" is becoming a title that changes hands more often, not a once-in-a-generation event. For governments preparing for November's COP31 climate summit in Türkiye, the Berkeley Earth update adds a fresh, data-driven reason to treat the gap between current pledges and needed cuts as urgent rather than theoretical.
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Frequently Asked Questions
What did Berkeley Earth actually forecast?
Berkeley Earth's September 2026 update gives roughly a 96% chance that 2026 will narrowly exceed 2024 to become the warmest year on record, up from about 93% in August, with a second-place finish at about 4%.
Why did the forecast change so much during 2026?
At the start of 2026 the chance was only about 12%, falling further by May. The emergence of a record-breaking El Niño then flipped the calculation, as Pacific warming pushed global temperatures higher.
Do all temperature trackers agree?
No. NOAA expects 2026 to finish a close second rather than first, while the EU's Copernicus service ranks 2026 as the second hottest year to date using data through September. Different datasets and methods produce slightly different rankings.
What is El Niño, and why does it matter for global temperature?
El Niño is a natural warming of the eastern tropical Pacific that pushes ocean heat and moisture into the atmosphere for months, temporarily adding to human-caused warming and shifting rainfall, drought and storm patterns worldwide.
Could 2027 be even hotter?
Scientists expect so, according to Bloomberg's report, because the temperature response lags the Pacific peak by several months — meaning much of this El Niño's warming influence is expected to carry into 2027.
Sources
- Berkeley Earth, "September 2026 Temperature Update," October 2026
- Bloomberg via Moneyweb, "Odds of 2026 becoming the hottest year surge higher with El Niño," 24 October 2026
- Reuters, "Super El Niño identified in September, China's climate centre says," 9 October 2026
- European Union Copernicus Climate Change Service, data through September 2026, as reported October 2026
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