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El Niño is (probably) coming back later this year.

And this time, it’s unfolding against a backdrop of unusually warm oceans and an even warmer climate system than the last time we experienced this natural climate pattern.

Here is what you need to know about it.

What is El Niño?

The term El Niño is part of a broader phenomenon called El Niño-Southern Oscillation, or ENSO. It’s a recurring climate pattern involving changes in sea surface temperatures across the central and eastern tropical Pacific.

Copernicus, a European climate data service, reported that in March 2026, the average sea surface temperatures in the Pacific reached 20.97°C – the second-highest value ever recorded for March, which suggests a likely transition toward El Niño conditions.

The El Niño-Southern Oscillation is one of the planet’s most important natural mechanisms through which the ocean and atmosphere exchange energy and reorganize the global climate from year to year.

The phenomenon has three phases: the warm phase is El Niño, the cool phase is La Niña, and between the two lies a neutral or transitional phase, when neither dominates clearly. The changes occur in the tropical region of the Pacific Ocean, within 700 miles of the equator.

The consensus among climate models – including those from NOAA – indicates with high probability the onset and subsequent intensification of El Niño starting in fall 2026, with some models suggesting it could be an unusually intense event.

We can anticipate more heat waves with a strengthening El Niño, along with more extreme events ranging from heavy rainfall to drought. El Niño tends to intensify the subtropical jet stream, favoring wetter conditions and greater storm activity across the southern United States and northern Mexico, while the northern United States and Canada experience a relatively warmer and drier pattern, affecting snow cover and water availability. At the same time, the effects of El Niño usually reduce the frequency and intensity of hurricanes in the Atlantic Ocean.

The return of El Niño is not synonymous with climate change

El Niño is a natural phenomenon of the ocean-atmosphere system. But when it coincides with a planet already warmed by human activity, its effects can be amplified. The World Meteorological Organization warned that during the last El Niño period (2023–2024), the combination of El Niño and climate change hit Latin America and the Caribbean with greater force, worsening droughts, heat waves, wildfires, extreme rainfall, and other impacts with significant human and economic costs.

El Niño affects more than the Pacific region

Although El Niño originates in the equatorial Pacific Ocean, its effects extend to other regions of the planet through processes known as climate teleconnections – atmospheric links that allow massive cloud formations to develop as a result of the enormous evaporation generated by the warming of ocean waters.

El Niño disrupts what is known as the Walker Cell or Walker Circulation, a tropical atmospheric circulation system that transports heat, moisture, and energy on a large scale. These disturbances propagate through the atmosphere in the form of planetary waves, modifying global pressure and wind patterns. As a result, El Niño’s influence reaches the Atlantic Ocean and the Caribbean, where significant changes in regional climate occur.

Among these effects are a tendency toward drier conditions in certain periods due to descending air and a redistribution of heat that contributes to higher temperatures and more intense heat waves. In short, even though El Niño occurs far from where most Yale Climate Connections readers live, its impact is clearly felt because Earth’s climate system is interconnected, and atmospheric disturbances can travel vast distances.

During El Niño, increased variability in wind direction and speed – which inhibits hurricane formation – can act as a buffer against hurricane activity. However, hurricane formation in the Atlantic depends on multiple factors, including conditions in the Atlantic itself – such as sea surface temperatures, atmospheric moisture, and the Azores High, a large semipermanent center of high atmospheric pressure that sits over the North Atlantic near the Azores islands. And when it comes to hurricanes, we should never let our guard down completely.

In general terms, precipitation tends to be greater during La Niña or neutral years than during El Niño years. This does not mean the disappearance of all rainfall. But it does suggest a greater probability of rainfall deficits, water stress, and, in some cases, the development of drought conditions – which could worsen the drought already affecting Southern and Western U.S. states.

El Niño is not here yet

According to the most recent diagnostic discussion from NOAA’s Climate Prediction Center, current conditions are ENSO-neutral. That same assessment indicates that neutral conditions are likely through May, April, June, and July 2026, potentially extending through September, at which point a transition to the warm phase of ENSO could begin. All forecasting centers emphasize that significant uncertainty remains regarding its ultimate intensity.

El Niño does not arrive on a fixed schedule

Both NOAA and other scientific bodies agree that it appears irregularly, generally every two to seven years, though the average tends to fall closer to every three to four years. Episodes typically last between nine and 18 months, and in some cases, somewhat longer due to the effects of global warming.