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El Niño set to become very strong, raising risks of extreme weather into 2027
*El Niño is firmly established and is expected to strengthen further
*WMO Forecasts show near 100% likelihood that it will persist through February 2027
*Exceptionally warm tropical Pacific Ocean conditions support further intensification
*A very strong El Niño can significantly shift rainfall and temperature patterns worldwide and fuel extreme weather
*WMO and National Meteorological and Hydrological Services step up preparedness and early-warning efforts for an exceptional event
Geneva, Switzerland, 3 September 2026 (WMO): El Niño is firmly established and will intensify into a very strong event in the coming months, with big impacts on rainfall and temperature patterns and associated risks of floods, drought and extreme heat, according to a new update from the World Meteorological Organization (WMO).
Forecasts from WMO’s Global Producing Centres indicate an “exceptionally high likelihood of nearly 100%” that El Niño will persist through to February 2027. This is the first time that a WMO El Niño/La Niña Update has been so unequivocal, reflecting the strong agreement within WMO’s extensive network.
Fueled by exceptionally warm ocean conditions across the tropical Pacific, El Niño is expected to strengthen further during the coming months to a very strong intensity before peaking towards the end of this year, with climate impacts continuing well into 2027.
“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. The race now is between rising risks and our commitment to take climate action and protect people. We must win that race,” said UN Secretary-General António Guterres
“El Niño in Spanish means boy child – but it has the potential to deliver a massive blow to communities and economies across the world. We are already seeing disruption and devastation from droughts and floods and we expect these impacts to increase as El Niño intensifies,” said WMO Secretary-General Celeste Saulo.
“This exceptional El Niño demands exceptional preparation and response. Never before in the 50-year history of the World Meteorological Organization have we launched such a major mobilization with National Meteorological and Hydrological Services who are on the frontline of delivering the forecasts and services to save lives and livelihoods,” she said.
“WMO is committed to working closely with partners across the United Nations and humanitarian system to provide the climate intelligence and insights needed to support disaster management and climate-sensitive sectors like agriculture, health, energy and water resources,” she said. “We have no time to lose.”
Exceptional ocean heat in the tropical Pacific
Sea surface temperatures across the central-eastern equatorial Pacific, the region at the heart of El Niño, are already well above average – one of the tell-tale signs of El Niño – and are continuing to rise.
The widely used Niño 3.4 index, which measures sea surface temperature anomalies in central-eastern equatorial Pacific has strengthened markedly from an average +1.5 °C above normal during May-July 2026 and +2.0 °C above normal in July. Weekly values subsequently increased further between late July and mid-August, ranging from approximately +2.2 °C to +2.6 °C above average, indicating continued intensification.
Even more exceptional warmth is present below the ocean surface. In some areas, subsurface ocean temperatures were more than 8°C above average during July and early August.
Together, the surface and subsurface ocean conditions provide strong support for continued El Niño conditions and the potential for further strengthening during the coming months, the Update says.
Confidence in the outlook is high. Strong and mutually reinforcing oceanic and atmospheric signals, together with close agreement among seasonal prediction systems indicate that El Niño will persist at least into early 2027.
Very Strong El Niño does not mean the same impacts everywhere
El Niño and La Niña are among the most powerful naturally occurring influences on the global climate system. A very strong event increases the likelihood of major changes in rainfall, temperatures and atmospheric circulation across many regions of the world.
However, the strength of an El Niño event alone does not determine how severe its impacts will be in any individual country or region.
Its effects vary according to location and season and can be modified by other climate drivers, including conditions in the Indian and Atlantic Oceans.
WMO has therefore issued a complementary Global Seasonal Climate Update, which brings together information about El Niño and other major climate drivers, enabling a more refined picture of expected conditions.
For September–November 2026, WMO 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 (IOD) is also expected to develop, reaching a September-October-November 2026 seasonal mean value of 0.9°C. Meanwhile, the equatorial Atlantic basin is forecast to remain generally warm, with SSTs 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.
Turning forecasts into early action
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.
El Niño generally begins developing between March and June and reaches its peak intensity between November and February. Its impact on global temperatures can extend beyond the period of peak ocean warming and be most pronounced in the year after development.
Because El Niño can reshape weather and climate patterns thousands of kilometres away from the tropical Pacific, reliable forecasts provide governments, humanitarian agencies, businesses and communities with valuable time to prepare.
WMO Members and partners will therefore continue to closely monitor the evolution of the event and regularly update forecasts of its likely regional impacts.
National Meteorological and Hydrological Services remain the authoritative source of official warnings and locally relevant climate information.
El Niño is a natural climate phenomenon and is not caused by climate change.
Expert Reaction
These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.
Chris Brandolino, Earth Sciences New Zealand Chief Scientist – Weather and Seasonal Forecasting
"The latest Global Seasonal Climate Update from the WMO lays it bare: El Niño is here and it is set to tilt the odds for unusual to extreme weather. Its impacts are already being felt here in NZ. Strong El Niño conditions continue in the tropical Pacific and are now prominently influencing New Zealand’s weather patterns. This is reflected by the recent increase in wind and, for lower and western areas of the South Island, heavy rain.
"It’s important to remember that El Niño means different things for different parts of the country. For those in the northern and eastern areas of both islands, in particular the North Island, dryness is a genuine concern. This is because rainfall is expected to be less than normal, and as we move deeper into spring, the effects of reduced rainfall will emerge.
"Additionally, because stronger than usual wind will favour a westerly direction, or some version of it, areas east of New Zealand’s mountains (think Southern Alps) will have periods of very warm temperatures. Like a bathroom hand dryer, wind and heat are highly effective at removing moisture. Where all these conditions converge, there will be enhanced drying of soils and vegetation, creating challenges for water-reliant sectors. Fire and Emergency New Zealand anticipates these same areas – northern and eastern regions of both islands – will have an elevated risk for wildfire this spring.
"For the lower and western South Island, rainfall and wind speeds are expected to be abnormally high, increasing the odds of flood and landslips, particularly over time. Impacts to the primary sector could also be noteworthy. For the western and lower North Island, dryness is more uncertain bears watching. High wind, however, is more of a certainty, and like the South Island, may prove to be societally disruptive at times.
"What happens beyond spring is still coming into focus. Earth Sciences New Zealand updates the long range, or seasonal climate outlooks, each month. For day-to-day forecasts, including severe weather watches and warnings, people are encouraged to rely on MetService.
"For more on El Niño and to see our live strength tracker please visit our explainer El Niño 2026 what you need to know."
