The World Meteorological Organization said on October 8 that El Niño would strengthen before peaking around December 2026. The warming of the equatorial Pacific is expected to raise temperatures across much of the world. Changes in rainfall could increase drought and flood risks in different regions.

The UN weather and climate agency puts the probability of the event persisting through February 2027 at nearly 100%. Its secretary-general, Celeste Saulo, said it could rank among the strongest episodes recorded since at least 1950.

Pacific temperatures could reach record levels

The WMO expects record sea-surface temperatures in the central and eastern tropical Pacific during October, November and December. Measurements in Niño 3.4, a Pacific reference region used to track El Niño, already show a substantial rise.

Temperatures there averaged 1.6°C above normal in June 2026, increasing to 2.5°C above normal in August, the agency said. For October–December, it forecasts a departure from normal of about 3.7°C, with the peak around December.

That would exceed the previous record of 2.6°C above normal, measured between November 2015 and January 2016. The projected record remains a forecast, rather than an observed temperature.

A natural cycle with global effects

El Niño is a natural climate phenomenon involving warmer surface waters in the central and eastern equatorial Pacific. It typically occurs every two to seven years and lasts about nine to 12 months. The current episode began developing in June 2026.

The WMO said its effects could compound those of human-caused climate change. Alongside higher temperatures, El Niño changes patterns of winds, atmospheric pressure and rainfall. The outlook does not specify how severe those effects will be in individual countries.

Drought in Central America is already reducing harvests and causing livestock losses. In India, severe disruptions to the monsoon are putting crops at risk.

Forecast draws on 13 meteorological centres

The forecast reflects a consensus among 13 national and international meteorological centres. It also draws on real-time observations from ocean buoys, satellites and other monitoring systems coordinated by the WMO.

Saulo said El Niño releases heat stored beneath the ocean surface rather than adding new heat to the planet. She said the ocean was the warmest measured, leaving more stored heat available for release.

The WMO also considers conditions beyond the Pacific in its seasonal outlook. Sea-surface temperatures in the tropical Atlantic are expected to remain above normal.