El Niño is now firmly established and is expected to strengthen into a very strong event in the coming months, bringing major shifts in rainfall and temperature patterns and increasing the risk of floods, drought and extreme heat.
The assessment was issued on Thursday, 3 September, in a new update from the World Meteorological Organisation (WMO).
WMO is a specialised agency of the United Nations (UN) that focuses on the Earth’s atmosphere, climate, weather, and water resources
According to the WMO, forecasts from its Global Producing Centres show an exceptionally high likelihood of nearly 100 per cent that El Niño will persist through to February 2027. The organisation said it was the first time an El Niño/La Niña Update had been so unequivocal, reflecting strong agreement across its network.
Fuelled by exceptionally warm conditions across the tropical Pacific, El Niño is expected to continue strengthening and reach very strong intensity before peaking towards the end of this year, with climate impacts continuing well into 2027.
UN Secretary-General António Guterres said: “El Niño is being supersized before our eyes. The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up. Sea surface temperatures are rising, temperatures keep climbing, and the world is in the danger zone of extreme weather.”
WMO Secretary-General Celeste Saulo said El Niño — Spanish for boy child — had the potential to deliver a massive blow to communities and economies.
“We are already seeing disruption and devastation from droughts and floods, and we expect these impacts to increase as El Niño intensifies,” she said.
“This exceptional El Niño demands exceptional preparation and response. Never before in the 50-year history of the World Meteorological Organisation have we launched such a major mobilisation with National Meteorological and Hydrological Services who are on the frontline of delivering the forecasts and services to save lives and livelihoods.”
The WMO said sea surface temperatures across the central-eastern equatorial Pacific, the region at the heart of El Niño, were already well above average and continuing to rise.
The widely used Niño 3.4 index, which measures anomalies in that region, strengthened markedly from an average of 1.5°C above normal during May to July 2026 to 2.0°C above normal in July. Weekly values between late July and mid-August rose further to between 2.2°C and 2.6°C above average.
Even more exceptional warmth was recorded below the surface, with subsurface temperatures in some areas more than 8°C above average during July and early August.
Together, the surface and subsurface conditions provide strong support for continued El Niño conditions and further strengthening, the update says.
Confidence in the outlook is high, with strong and mutually reinforcing oceanic and atmospheric signals and close agreement among seasonal prediction systems indicating El Niño will persist at least into early 2027.
The WMO said El Niño and La Niña are among the most powerful naturally occurring influences on the global climate system and a very strong event increases the likelihood of major changes in rainfall, temperature and atmospheric circulation.
It, however, said that the strength of an event alone does not determine how severe its impacts will be in any individual country or region. Effects vary by location and season and can be modified by other drivers, including conditions in the Indian and Atlantic Oceans.
For that reason, the WMO has issued a complementary Global Seasonal Climate Update. For September to November 2026, multi-model forecasts indicate an increased likelihood of above-normal temperatures across almost all land areas, alongside rainfall patterns showing a pronounced and classic atmospheric response to the strong Pacific El Niño.
A positive phase of the Indian Ocean Dipole is also expected to develop, reaching a seasonal mean of 0.9°C for September to November, while the equatorial Atlantic basin is forecast to remain generally warm, with sea surface temperatures in both the North and South Tropical Atlantic staying above normal. These conditions may reinforce, weaken or alter typical El Niño impacts in different regions.
El Niño is characterised by warming of ocean surface temperatures in the central and eastern equatorial Pacific. It typically occurs every two to seven years, lasts nine to twelve months, generally begins developing between March and June and peaks between November and February. Its impact on global temperatures can extend beyond the period of peak ocean warming.
The WMO stressed that El Niño is a natural climate phenomenon and is not caused by climate change.
