What Is A 'Super El Niño', The Extreme Weather Event Experts Think Will Hit This Summer?

Expert comment provided by Professor Emeritus of Geophysical and Climate Hazards at University College London, Prof Bill McGuire. He is also the author of The Fate of the World: A History And Future Of The Climate Crisis, due out on 21 May.

The start of spring is usually considered a little early to predict a weather phenomenon known as an El Niño, which involves the warming of the ocean surface and is linked to extreme weather events.

That’s down to a factor called the “spring predictability barrier”; from March to May, the climate systems of the Pacific Ocean are unusually unpredictable.

But many experts have cautiously done so anyway. The National Oceanic and Atmospheric Association has given greater odds than ever that we’ll have an El Niño in place by midsummer.

Every single model ensemble member involved in the recent European Centre for Medium-Range Weather Forecasts release – and there were over 20 of them – said there’s likely to be a pretty strong El Niño by June. In fact, some predict a “super El Niño”. 

But what is an El Niño, why might it happen, and how does it affect the planet? 

What is an El Niño and a super El Niño?

Speaking to HuffPost UK, Prof Bill McGuire, a professor specialising in climate hazards, said: “El Niño is a climate phenomenon that develops every few years, and which involves the eastern and central equatorial Pacific Ocean becoming hotter than normal.” 

Super El Niños are relatively rare, he added.

It “has only happened five times in the last three-quarters of a century.

“During a normal El Niño, the temperature of the equatorial Pacific Ocean typically reaches 0.5°C or more above normal. If this figure reaches 1.5-2°C, the event is described as a super El Niño. 

“The most extreme El Niño ever recorded happened in 2015-16, when the sea temperature exceeded 2.5°C. Broadly speaking, the bigger the El Niño, the greater its impacts on the world’s weather.”

Why is an El Niño predicted in 2026? 

We still don’t know for sure whether we’ll have an El Niño in 2026. And they do happen every few years or so – but global warming might make them more extreme.

“Global heating due to human activities is driving more powerful El Niños, and all the early indicators point to another big one starting to emerge as soon as the summer,”  Prof McGuire told us.

“The signs are that it could even be the biggest for a century and a half.”

How would a Super El Niño affect the planet?

“This has a huge impact on global weather, bringing drought, floods and other extreme weather right across the planet. The cost of weather disruption caused by the super El Niños of 1982-83 and 1997-98 has been calculated as being in the trillions of dollars,” the professor explained. 

“El Niños also result in a general heating up of the world as a whole. The 2023-24 El Niño led to record-breaking global temperatures in 2024.

“A super El Niño later this year is likely to see the global average temperature rise since pre-industrial times smashed again, and it wouldn’t be a surprise to see both this year and next breaching the 1.5°C dangerous climate change guardrail.” 

How would a Super El Niño affect the UK? 

In the UK, he added, there tends to be a “lag” in how the phenomenon affects us.

While it “might help to push up summer temperatures”, its greatest short-term effect on us usually appears months later. 

“Generally, El Niño events bring colder UK winters, although it is not a hard and fast rule,” the professor shared.

Of course, the whole world – the UK very much included – would be affected should we exceed 1.5°C in global warming.