The World Meteorological Organization (WMO) is warning countries across the world that an El Niño extreme weather event is set to arrive in the coming months with 90% certainty.

Fuelled by unusually warm ocean waters in the tropical Pacific, El Niño conditions are developing and are set to influence global temperature and rainfall patterns, increasing the risk of extreme weather over the coming months.

The warning comes in a new WMO El Niño/La Niña Update released today which indicates an 80% likelihood of an El Niño event during June–August 2026. Probabilities for this to continue until at least November are near or above 90%. Although some uncertainty remains about El Niño peak strength and timing, most forecast models suggest it will be at least moderate – and possibly strong.

Key messages in the update include:

• Warm ocean waters are fueling the development of El Niño
• El Niño typically increases global temperatures and drives more extreme weather and rainfall patterns
• Above average temperatures forecast nearly everywhere for June to August
• Advanced forecasts help in preparations to protect lives and livelihoods
• Time for informed decision-making, planning and preparedness is now

The WMO El Niño/Updates are the world’s most authoritative source of information for governments, humanitarian agencies and climate-sensitive sectors like agriculture, health, energy and water management.

UN Secretary-General António Guterres, said in a video statement:

“The science is clear: El Niño is arriving on our doorstep in the coming months with 90% certainty. The world must treat it as the urgent climate warning it is. El Niño conditions will pour fuel on the fire of a warming world. Impacts will hit even harder, travel even farther, and cross borders with devastating speed. The only effective response is climate action equal to the crisis – ending the addiction to fossil fuels, accelerating the shift to renewables, protecting the most vulnerable, and delivering early warning systems for all.”

In late April to mid-May, the sea-surface temperature in the central-eastern Equatorial Pacific – the area used as a monitoring reference - was approaching El Niño thresholds, according to observations from different platforms used by WMO.

The increasing surface anomalies are being fed by unusually warm subsurface conditions across the tropical Pacific, with temperatures exceeding 6 °C above average and providing a substantial reservoir of heat that is contributing to the observed surface warming.

Meanwhile, the Southern Oscillation Index – which is the atmospheric component of El Niño – is also consistent with developing El Niño conditions.

Potentially strong El Niño event will exacerbate drought, heavy rainfall and increase risk of heatwaves

WMO Secretary-General Celeste Saulo commented:

“We need to prepare for a potentially strong El Niño event – which will exacerbate drought and heavy rainfall and increase the risk of heatwaves both on land and in the ocean. The most recent El Niño, in 2023-24, was one of the five strongest on record and it played a role in the record global temperatures we saw in 2024.

“The WMO community will be carefully monitoring conditions in the coming months to inform decision-making by governments, humanitarian agencies and climate-sensitive sectors. Advance seasonal forecasts and early warnings are vital to save lives and cushion the impact on our economies and our communities.”

El Niño and La Niña are opposite phases of the El Niño–Southern Oscillation (ENSO); one of the most powerful naturally occurring climate patterns on Earth.

El Niño is characterized by a warming of ocean surface temperatures in the central and eastern Equatorial Pacific. It typically occurs every two to seven years and lasts around nine to twelve months.

It generally begins developing between March and June and reaches its peak intensity between November and February, with impacts on global temperatures typically being most pronounced in the second year after development