El Niño has now taken hold firmly in the tropical Pacific and will turn very strong, the World Meteorological Organisation (WMO) said on September 3. Floods, drought and extreme heat will remain a risk into 2027.
Seasonal forecasts point to a milder winter for Europe, but meteorologists do not rule out cold snaps and rough weather. An unusually warm winter is not a sure thing, they warn. The event forms in the tropical Pacific, and its effects reach Europe only indirectly.
The WMO puts the chance El Niño will last until February 2027 at almost 100%, the most confident forecast it has ever issued. In its latest seasonal climate outlook, the organisation says the event will grow even stronger.
El Niño strengthened over the past month, the Climate Prediction Center at the US National Oceanic and Atmospheric Administration said in an assessment on September 10. It puts the chance El Niño will turn very strong in the northern hemisphere autumn and winter of 2026-2027 at over 90%. The chance it will still be going through December, January and February is near 100%.
Water in parts of the eastern equatorial Pacific is more than 3 degrees warmer than usual. The Niño-3.4 index stood at 1.8 degrees in August, and the WMO expects the average for September, October and November to run around 3.6 degrees.
El Niño returns every two to seven years and lasts nine to 12 months. The last one, in 2023-2024, ranks among the five strongest on record, the WMO says, though the 2015-2016 event was even stronger. The Intergovernmental Panel on Climate Change (IPCC) says, with medium confidence, that extreme El Niño events will hit roughly twice as often this century as they did in the last.
What this means for people on the ground is the subject of a new analysis from the UN Development Programme (UNDP), which looks at Asia and the Pacific. It was written by a UNDP specialist on recovery and early warning systems for Eurasia, together with the head of the regional tsunami project at the organisation's regional centre.
El Niño is expected to peak around the end of 2026, with its strongest phase hitting around November and December. The worst damage to farming and food supplies may come later, in late 2026 and through 2027, a UN regional review shows. On mainland Southeast Asia, the heaviest impact has historically landed between February and May of the second year of an El Niño episode.
Drier weather, water shortages, crop losses, forest fires and extreme heat can carry on, or even get worse, even once El Niño itself starts to fade.
On August 26, a flash flood and landslide that began high in the Himalayas struck communities along the Bhote Koshi and Trishuli rivers in Nepal. In late September, heavy rain flooded Bangkok, and Typhoon Dujuan dumped record rainfall and set off floods and landslides across greater Tokyo. None of these events is directly tied to El Niño, UNDP notes, but together they show how little room these regions have to spare when such a blow lands.
A rapid UNDP check after the Nepal disaster found that a large share of people in the hit communities were already worse off than average before the flood struck. Disasters hit hardest where people have been left unprotected by a lack of development, the authors say.
The blows do not land evenly, they add. A small farmer who loses a crop also loses next season's income. An outdoor worker loses a day's pay to the heat. A family with no savings, no insurance and no safety net has nothing to fall back on. High fuel, fertiliser and food prices could turn climate-driven crop losses into a deeper food shortage by 2027.
Unlike an earthquake, El Niño gives warning, UNDP points out. The months before it peaks are the most valuable window to act, and that window is closing.
UNDP lists five things governments and their partners should do now. Forecasts need to lead to decisions. There needs to be one shared, regularly updated picture of the risk. Clear warnings must reach the people most at risk, including women and remote communities, through channels they trust. Countries also need to be ready to act early: checking the triggers that release aid, drawing up emergency plans, and lining up money and supplies in advance.
Safety nets need to be able to grow fast. That means ready-made registries, payment channels and a clear way to decide who gets help, set up before families are forced into harmful choices just to get by. Development programmes already under way need to adapt to the new conditions, and recovery planning should start before it is needed, with an agreed process for assessing damage, baseline data, clear roles for who coordinates what, and money set aside.
How hard El Niño hits a community is decided years in advance, the authors argue. It depends on where roads and towns were built, how water is managed, who is covered by a safety net, and whether there is money set aside to absorb the shock.
That is why UNDP does not treat El Niño as a one-off emergency but as core, ongoing work: ongoing monitoring, preparation, response and recovery, built into national plans and budgets. Climate and disaster risk should be written into planning, public spending and building rules, the organisation says, and the bodies that run water, health, education and local services need to be made stronger so they can hold up under pressure.
Safety nets need to be able to respond fast to shocks, and money for risk should come through several channels, from reserve budgets and standby loans to insurance, so funds flow before losses hit rather than after. The cost of acting early is part of the cost of a slow recovery, the authors write. El Niño will come back, and so will La Niña, on a planet that keeps warming.