WMO: El Niño strengthening, expected to peak in December

El Niño will intensify even more before peaking in December, the World Meteorological Organization (WMO) said on Thursday, warning it could be among the strongest witnessed since at least 1950.

The naturally occurring weather phenomenon is set to bring higher temperatures to much of the planet, the UN's weather and climate agency said, with its impact compounding the effects of man-made climate change.

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

"It is likely to bring above-average temperatures to much of the globe and shift rainfall patterns, increasing the risk of drought and floods in different regions."

El Niño warms surface temperatures in the central and eastern equatorial Pacific Ocean, bringing worldwide changes in winds, pressure and rainfall patterns.

It typically takes place every two to seven years and lasts around nine to 12 months.

Conditions oscillate between El Niño and its opposite La Niña, with neutral conditions in between.

El Niño 'strengthening rapidly'

Sea-surface temperatures in the central and eastern tropical Pacific are forecast to reach record levels during October-November-December 2026, reflecting the rapid strengthening of the El Niño event, the WMO said. The forecast is based on a consensus among 13 leading national and international meteorological centers.

"El Niño is firmly established and strengthening rapidly," said WMO chief Celeste Saulo.

WMO forecasts indicate a near-100% likelihood that the event will persist through February 2027 and could rank among the strongest since at least 1950.

Saulo said El Niño does not add new heat to the planet but releases heat stored in the ocean.

"The ocean it's drawing from is the warmest we've ever measured it. There is simply more heat available to release," she said.

Sea temperatures record

The index which measures sea surface temperature anomalies across the central-eastern equatorial Pacific – the region at the heart of El Niño – increased from 1.6 degrees Celsius above normal in June to 2.5 degrees Celsius above normal in August.

For October-November-December, the anomaly is forecast to reach approximately 3.7 degrees Celsius above normal.

This would be the highest since observations began, eclipsing the previous record of 2.6 degrees Celsius set in 2015-2016.

The last El Niño contributed to making 2023 the second-hottest year on record and 2024 the all-time high at around 1.55 degrees Celsius  above the 1850-1900 pre-industrial average.

While El Niño usually peaks between November and February, the resulting spike in temperatures typically comes later.

This event is already hitting some regions hard, including in Central America, where animals and crops are dying from drought.