Sea-surface temperatures across the central and eastern tropical Pacific are projected to climb to unprecedented levels between October and December 2026, driven by a rapidly strengthening El Niño climate pattern that threatens to disrupt global weather systems, economies, and ecosystems.
The World Meteorological Organization issued its monthly Global Seasonal Climate Update, detailing how the large-scale climate driver is intensifying ahead of an anticipated peak in December. The phenomenon is expected to trigger above-average global temperatures and alter precipitation cycles, elevating the probability of severe droughts and floods across various parts of the world.
“El Niño is firmly established and strengthening rapidly. WMO forecasts indicate a near-100 per cent likelihood that it will persist through February 2027, potentially being one of the strongest since at least 1950,” said WMO Secretary-General Celeste Saulo.
The consensus behind this near-certainty projection relies on data pooled from 13 national and international meteorological centers spanning Washington, Tokyo, London, and Pune. This modeling is underpinned by real-time observations collected from ocean buoys, satellites, and radiosondes under WMO coordination.
Pacific Ocean Anomalies and Global Temperature Drivers
At the core of the event, sea-surface temperature anomalies across the central-eastern equatorial Pacific—tracked via the Niño 3.4 index—surged from an average +1.6 °C above normal in June 2026 to +2.5 °C above normal in August. For the final quarter of the year, the seasonal average anomaly is projected to reach approximately +3.7°C, eclipsing the previous peak of +2.6 °C recorded between November 2015 and January 2016.
Speaking at the Global Heat Forum in Bangkok, Saulo emphasized the mechanism driving the warmth. “El Niño doesn’t add new heat to the planet. It releases heat the ocean has already been storing beneath the surface – which is why a strong event so often becomes one of the hottest years measured (as with 2024),” she noted. “The ocean it’s drawing from is the warmest we’ve ever measured it. There is simply more heat available to release.”
Additional ocean basins are also influencing the broader seasonal outlook. A positive Indian Ocean Dipole, which heavily dictates regional rainfall, is anticipated to reach a peak in October before tapering off, with a forecasted seasonal anomaly of about +0.5°C. Meanwhile, equatorial Atlantic sea-surface temperatures are predicted to stay above normal.
Monitoring the El Niño Peak and Regional Outlooks Through February 2027
The unfolding climate shift bridges multiple monitoring systems, integrating the monthly update with the agency’s quarterly El Niño/La Niña assessments to track broader shifts in the El Niño–Southern Oscillation, the Indian Ocean Dipole, and tropical Atlantic temperatures.
As observational data continues to feed into predictive models, meteorological centers will monitor the transition from September initial conditions toward the forecasted December apex. With the event locked in to persist through February 2027, international agencies and regional governments face an extended period of heightened vigilance regarding flood and drought management.
