Prepare for El Niño, UN warns - it could be the strongest in decades

Scientists fear the combined effects of El Niño and human-caused climate change could reshape weather around the world

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By Mark Poynting, Erwan Rivault, Becky Dale and Jess Carr 2 June 2026 Climate & Science

A new phase of the natural El Niño weather pattern could begin in a matter of weeks, the UN has warned, boosting temperatures on a planet already under strain from climate change.

The World Meteorological Organization said this El Niño is likely to strengthen over the rest of 2026, driving more extreme weather around much of the globe.

Several forecasts from national weather agencies suggest it could end up as one of the strongest ever recorded - a possible so-called “super” El Niño.

Predicting the exact timing and strength of El Niño can be challenging, and scientists have been watching conditions in a tell-tale region of the central Pacific for clues.

Map of the globe centred on the Pacific Ocean with a box around the main Niño monitoring region at the equator. The sea surfaces are shaded on a divergent scale from blue, representing colder-than-average temperatures, to white representing average, to orange, representing above-average temperatures. Along the equator and across the whole monitoring region box the waters are blue and elsewhere orange.

In December these waters were cooler than average - shown here in blue - with no El Niño to be seen.

Map of the globe centred on the Pacific Ocean with a box around the main Niño monitoring region at the equator and a circle around a patch off the west coast of equatorial South America. The sea surfaces are closer to white in the monitoring region box, with a dark orange section inside the eastern circled area.

But three months later, the picture had changed.

The central Pacific was warmer - shown here in orange - with very warm waters emerging off the coast of South America.

By April a looming El Niño was unmistakable. Temperatures in the main monitoring region were rising - and these waters have only continued to warm since.

El Niño forms when a switch in wind patterns allows warmer waters to spread across the tropical Pacific Ocean.

And while an El Niño event had been anticipated, many scientists believe this one could be unusually powerful.

“We're very confident that there's a big event coming,” said Prof Adam Scaife, head of monthly to decadal prediction at the UK Met Office. “It may even be a record event.”

Bar chart with grey bars that extend above and below a middle line marked zero degrees. The y-axis shows the change from that average, with minus two at the lower end and higher than plus-two at the upper end. The x-axis shows every month from January 1950 to March 2026.

Sea surface temperatures in the Pacific monitoring region naturally fluctuate above and below average.

The bar chart now shows certain bar segments in colour. Above plus 0.5 the bars are red and labelled El Niño. Below minus 0.5 the bars are blue and labelled La Niña. The tallest bars above plus-two are highlighted as "very strong El Niños", which have occurred only six times since 1950. The strongest was in 1982 and the most recent in 2015.

When they warm or cool by more than half a degree from the baseline over an extended period, conditions for El Niño or its cooler sibling La Niña are present.

Warming above two degrees indicates a "very strong" or so-called "super" El Niño.

The same bar chart with coloured segments remains, but the labels have disappeared. A new label to the right of the chart shows the range of possible temperatures forecast by different models at the likely peak of this El Niño in November 2026. They range from plus 1.8 to plus 3.3, with a central estimate of 2.7.

There have been only a handful of these cases since 1950. Forecasts suggest this new El Niño could equal past peaks - or even surpass them.

Part of the reason why scientists expect a strong El Niño lies deep below the ocean surface.

Data from satellites, buoys and ocean floats indicate a huge wave of unusually warm water - more than 6C above average in places - creeping eastwards across the Pacific, hundreds of metres deep.

The warmth of these waters “rival[s] some of the strongest El Niño events we have seen”, said Michelle L’Heureux, a physical scientist at the US science agency NOAA’s Climate Prediction Center.

That deep-sea heat is often a precursor to warmer waters at the surface - which then heat the air above, helping to disrupt weather patterns worldwide.

“El Niño conditions will pour fuel on the fire of a warming world," said UN secretary general António Guterres. "Impacts will hit even harder, travel even farther, and cross borders with devastating speed.”

No two El Niño events are the same, and different places can be affected at different times of the year.

But a strong El Niño typically fuels hot, dry weather in parts of South America, South East Asia and Australia, raising the chances of droughts and wildfires.

It can also weaken the Indian monsoon and bring drier conditions to northern parts of the Greater Horn of Africa - while heavier rainfall can increase the risks of flooding in the southern US.

El Niño can even increase the chances of a mild start and cold end to UK winters - although its links with weather in north-west Europe are not as strong.

Map of the globe with patches of colour to indicate possible impacts on precipitation patterns around the world. Areas in dotted green, such as the southern US, horn of Africa and east Asia, are likely to be wetter than normal. Areas in dotted brown, such as Australia, India and the Amazon, are likely to be drier than normal.

Past events have been linked to spikes in food prices and hundreds of billions or even trillions of dollars in lost income globally, as crop failures and trade disruptions ripple through supply chains and economies.

As El Niño typically peaks in strength around Christmas time, it is impossible to know for sure that it will be a record-breaker with months still to go.

El Niño is very sensitive to wind patterns, for example, which are difficult to predict far in advance - “the biggest wildcard” for El Niño, according to L’Heureux.

But even if El Niño falls short of “super” territory, the consequences could still be extreme.

That is because we have never experienced El Niño on a planet already so hot from human-caused climate change.

A line chart with a point for every month from January 1975 to March 2026. Each point represents the change in average global temperature that month from the pre-industrial average global temperature. Although there is variation between months, overall temperatures trend clearly upward with the most recent extremes above 1.5C.

These are monthly global air temperatures compared with those of the late 19th Century.

The same line chart is now shaded red to indicate all the months in which El Niño conditions were present in the Pacific monitoring region. Most of the highest peaks correlate with these periods and show when new global record temperatures were set.

Temperatures usually spike during El Niño years - perhaps by 0.2C for a strong event.

The same line chart keeps the red sections to indicate all the months in which El Niño conditions were present in the Pacific monitoring region and adds blue sections to indicate all the months in which La Niña conditions were present. These largely correspond to the lower points, even as overall temperatures are rising over time.

And they typically fall during La Niña.

A trend line is added to the fully coloured line chart to emphasise the increase.

But these spikes and falls are only temporary. The long-term warming trend is climate change.

The year “2027 is very likely at this point to be the [world’s] warmest year on record,” said Zeke Hausfather, a climate scientist with the Berkeley Earth group in the US.

In 1998, the world had “an incredibly strong El Niño event and an incredibly hot year for the time", he added. “If [that] happened today, it would be an incredibly cold year compared to the last two decades.”

“It just goes to show how big an impact humans are having on the climate.”

Data

Sea temperature maps

Data source: ERA5 C3S/ECMWF. Sea surface temperatures are compared with the 1991-2020 average.

El Niño temperature chart

Data source: Data source: Historical data from NOAA Relative Oceanic Niño Index, to March 2026. The Relative Oceanic Niño Index attempts to remove the influence of global warming to only show variations in the strength of El Niño and La Niña. Future projected range for November 2026 via Dr Zeke Hausfather. The forecast shows the estimated strength of El Niño based on six climate models from CanSIPS, NASA, NCAR and CFS. The range represents the middle 50% of model forecasts.

Precipitation impacts map

Data source: Lenssen, Goddard and Mason, 2020

Global temperatures chart

Data source: ERA5 C3S/ECMWF, NOAA Relative Oceanic Niño Index, data to March 2026. The regression trend line is indicative only.

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