The World Meteorological Organization’s global forecasting centres put the probability of El Niño persisting through February 2027 at nearly 100%. The WMO says its El Niño/La Niña assessment has never before produced such a clear forecast, reflecting strong agreement across its extensive forecasting network.
The WMO expects El Niño to strengthen over the coming months. It could become very strong by year-end, with effects that may continue into 2027.
Exceptionally warm tropical Pacific waters support that outlook, according to the organization. Its Nino 3.4 index, which measures sea-surface temperature departures from normal in the central and eastern equatorial Pacific, averaged 1.5°C above normal between May and July. In July alone, the departure reached 2.0°C. Weekly readings from late July to mid-August were around 2.2–2.6°C above normal.
The heat extends below the surface, too. In some areas, subsurface ocean temperatures during July and early August were more than 8°C above average. The WMO says both surface and subsurface conditions support El Niño’s persistence and further strengthening.
El Niño is a natural, periodic warming of eastern Pacific surface waters associated with weakening trade winds. It typically develops every two to seven years and usually lasts no more than a year. It can substantially change rainfall and temperature patterns worldwide, increasing the risk of floods, drought, extreme heat and other extreme weather events.
Storm clouds approach Buenos Aires, Argentina, during the 2024 El Niño, in the Southern Hemisphere summer.
UN Secretary-General António Guterres said El Niño is “growing stronger before our eyes.” He said scientific findings leave no doubt that the planet has entered uncharted waters that are becoming increasingly warm.
The WMO’s multi-model forecasts for September–November indicate increased odds of above-average temperatures across almost all land regions. Rainfall patterns may also reflect the atmospheric response typical of a strong El Niño over the Pacific.
But a strong El Niño doesn’t mean equally severe consequences everywhere. WMO Secretary-General Celeste Saulo emphasized that the phenomenon’s strength alone does not determine the severity of its effects in a particular country or region. Geography and season matter, and other climate factors, including conditions in the Indian and Atlantic oceans, can modify those effects.
Saulo said the WMO and national meteorological and hydrological services are stepping up preparedness and early-warning efforts for the exceptional event. That work must account for regional differences, even with the forecasting network’s near-certainty about El Niño’s persistence.
