El Niño to Strengthen Before Reaching Peak in December: UN

El Niño is expected to intensify further before reaching its peak in December and could become one of the strongest events recorded since at least 1950, the United Nations said Thursday.

The weather phenomenon is forecast to push temperatures above average across large parts of the world, compounding the effects of human-driven climate change, according to the World Meteorological Organization (WMO).

“El Niño will continue to intensify ahead of its forecast peak in December,” the WMO said in its monthly Global Seasonal Climate Update.

The agency warned that the phenomenon could bring above-average temperatures across much of the globe while altering rainfall patterns and increasing the risk of droughts and floods in various regions.

El Niño occurs when surface waters in the central and eastern equatorial Pacific Ocean become unusually warm, triggering changes in global wind, atmospheric pressure and rainfall patterns. It generally develops every two to seven years and lasts between nine and 12 months.

The climate system alternates between El Niño and its opposite phase, La Niña, with neutral conditions occurring between the two.

El Niño strengthening rapidly

Sea-surface temperatures in the central and eastern tropical Pacific are projected to reach unprecedented levels during October-November-December 2026, reflecting the rapid strengthening of the current El Niño, the WMO said.

The phenomenon is expected to influence weather patterns and affect economies, ecosystems and communities around the world. The forecast is based on a consensus among 13 leading national and international meteorological centres.

“El Niño is firmly established and strengthening rapidly,” WMO Secretary-General Celeste Saulo said.

The agency forecasts an almost 100% probability that El Niño will continue through February 2027, with the event potentially ranking among the strongest observed since 1950.

Saulo noted that El Niño does not create additional heat but instead releases heat stored in the oceans.

“The ocean it is drawing from is the warmest we have ever measured. There is simply more heat available to release,” she said.

Sea temperatures hit record levels

The index used to measure sea-surface temperature anomalies in the central-eastern equatorial Pacific rose from 1.6°C above normal in June to 2.5°C above normal in August.

For October through December, the anomaly is forecast to climb to around 3.7°C above average.

If realised, that would be the highest level recorded since observations began, surpassing the previous record of 2.6°C set during the 2015-16 El Niño.

The previous El Niño contributed to making 2023 the second-hottest year on record, while 2024 became the hottest, with global temperatures averaging about 1.55°C above the 1850-1900 pre-industrial level.

Although El Niño typically reaches its peak between November and February, its strongest temperature effects generally occur later.

The current event is already affecting several regions, including Central America, where drought has contributed to the deaths of animals and damage to crops.