A Big El Niño Event is Likely in 2026. But What’s the Context Behind the Headlines, and What are the Global Implications?

Key points

• A strong to very strong El Niño event is highly likely in 2026, with the official NOAA forecast calling for a ~67% chance of at least strong intensity by late autumn.
• The El Niño event is emerging against a backdrop of global warming, which, when combined, will likely make 2026 and/or 2027 the warmest years on record and amplify global hydroclimate extremes.
• This outlook implies opposite impacts on tropical cyclone across basins: a substantial decrease in overall storm count is likely in the Atlantic Basin amid a still-elevated intensity ceiling, with a strong increase in activity in the Central and East Pacific.

Understanding the forecast surrounding a potentially very strong event

The El Niño-Southern Oscillation (ENSO) is a primary driver of seasonal climate on a regional to global basis. El Niño involves a warming of sea surface temperatures (SSTs) in the central and eastern equatorial Pacific, coupled with weakened trade winds and shifted rainfall patterns. Its opposite phase, La Niña, features cooler-than-average waters driven by strengthened trade winds.

This year, all signs are increasingly pointing to a significant, if not strong to very strong, El Niño event in 2026. In fact, a majority of model ensemble members from leading global atmospheric and oceanic predictive centers are now explicitly predicting a so-called “Super El Niño” event by autumn–and the most recent official NOAA forecast calls for a ~69% chance of an event of at least strong intensity by peak hurricane season (ASO) and a ~48% chance of a very strong (“super”) event by late autumn (SON). From this still-early juncture, these are notably high odds indeed.

Confidence in this forecast has grown since February as oceanic and atmospheric trends increasingly align with predictive models. Current observations show key precursors: rapid warming near coastal Peru, a deep volume of anomalous subsurface warmth, and reinforcing westerly wind bursts in the atmosphere.

Why is the prospect of an especially strong event such a big deal? Fundamentally, a stronger El Niño means a much stronger seasonal predictive signal than what we have to work with over 90% of the time. This amplification, in turn, boosts our confidence in the magnitude and geographical distribution of the expected impacts. We’re not just expecting an El Niño; we’re bracing for one that could be widely substantive and perhaps even historic in its influence, exerting a powerful global weather “steering signal” for months to come. This strength elevates the prospect of various regional extreme events and associated hazards for a prolonged period, likely into late 2026 and perhaps even into early 2027.

Figure 2. Animation (from NOAA Climate Prediction Center) of the eastward trajectory of a large oceanic Kelvin wave and associated anomalous warm water volume, generated originally by westerly wind bursts earlier this spring. This vast area of far warmer than average water at depth is now surfacing, as of mid-late May, in the far eastern Pacific, west of Peru (at right of image).

El Niño in a warming world: A complex and potentially volatile combination

El Niño doesn’t occur in a vacuum. This year’s emerging event is taking place against a backdrop of persistent, human-caused global oceanic (as well as atmospheric) warming. This combination raises complex questions about how to interpret the expected impacts.

First, El Niño acts as a tropical ocean heat liberator. Its core function in the global Earth system is to release heat that has been temporarily stored in the deeper ocean layers. El Niño allows this “subducted heat” to be unearthed, raising global average temperatures temporarily. This dynamic puts 2026 and especially 2027—when the atmospheric warming signal typically peaks—on track to potentially be the warmest years on record due to the combination of a 1-2 year long El Niño-induced temperature spike atop continued escalation of long-term global warming.

The thermodynamic implications of this overall warmer world are profound, particularly when combined with an El Niño. Climate change increases the ceiling on global water vapor and hydroclimate extremes. This ties into a concept I call the “expanding atmospheric sponge” effect. Due to the Clausius-Clapeyron relation, the water vapor-holding capacity of the air increases exponentially with temperature. As temperatures rise, ambient air becomes “spongier”—about 7% larger per degree Celsius of warming. This dramatically increases the ceiling on precipitation intensity, leading to much heavier downpours. Simultaneously, the air’s “atmospheric thirst”—or evaporative demand—also increases, which means dry periods can become even more intense than they would amid cooler air. The net result is increasing global hydroclimate whiplash, and the temporary additional warming from a strong El Niño event may put an exclamation point on that broader trend.

To distinguish El Niño’s signal from long-term trends, weather and climate monitoring agencies (like the National Oceanic and Atmospheric Administration, or NOAA, in the United States) have recently begun to use climate change-aware metrics like the Relative Oceanic Warming Index (RONI). By removing the global tropical mean SST, the RONI accounts for the reality that while global oceans have warmed considerably in recent decades, the rate of warming has not been spatially uniform. Using the RONI in conjunction with other traditional ENSO metrics allows for a dual perspective for understanding physical risk:

1. The “global tropics mean removed” perspective, which is highly relevant to traditional global atmospheric teleconnections since they mainly arise from relative temperature differentials within the tropics, and
2. The “absolute SST” perspective, which is crucial for determining topline thermodynamic impacts, such as the sheer amount of moisture and energy available for storms. This dual perspective is essential for accurately framing discussions surrounding physical risk.

These perspectives are both important, as they yield different yet complementary information relevant to understanding weather and natural hazard risk in the months to come.

Tropical cyclone risk in 2026: Strong signals of opposite sign in different ocean basins

The looming El Niño forecast for 2026 dictates a distinct, though often complex, signature on tropical cyclone (TC) activity worldwide.

Atlantic Basin: Decreased TC count likely, but elevated ceiling intensity from historical warming remains

Historically, a strong El Niño generally decreases Atlantic basin activity, particularly in the Main Development Region (MDR). The key physical mechanisms are two-fold:

1. Vertical Wind Shear: El Niño tends to increase “hurricane-decapitating” vertical wind shear across the MDR, making it harder for storms to organize and sustain themselves.
2. Atmospheric Stability: There is often net downward upper atmospheric motion on a basin-wide basis, which essentially “puts a lid” on most developing storms, suppressing convection.

However, the outlook this year for the Atlantic is a bit of a mixed bag. A decrease in overall TC count does not necessarily translate to a proportional decrease in risk. Why? Because the Gulf of Mexico (GOM) and the subtropical Atlantic along the U.S. Eastern Seaboard remain anomalously warm, and this warmth is expected to persist into peak hurricane season. The fundamental risk is that if a storm manages to sneak through a window of opportunity created by natural intraseasonal variability—which can still produce short-lived active periods—those unusually warm ocean waters will give it extra fuel and a higher intensity ceiling. While it’s true that even in the quietest seasons, “it only takes one” major landfall to cause a potential disaster, a year like this one featuring profound basin-scale suppression yet a still-elevated thermodynamic ceiling accentuates that dynamic even more than usual.

Central and East Pacific Basin: Active season likely, with notable threats to Mexico and Hawaii

In contrast to the Atlantic, the East Pacific basin is expected to see significantly increased activity. The warming pattern of El Niño increases oceanic warmth and storm-favorable upward vertical motion in this region, which often increases both the frequency and intensity of TCs. The primary regions to watch are the Pacific (west) coast of Mexico, including Baja California, as well as the Hawaiian Islands. Although Hawaii represents a relatively small “target” for major storms to hit, the odds of such an event are considerably higher than baseline in a year like this one.

For the southwestern United States–including Southern California–strong or very strong El Niño conditions can increase the potential for unusual recurving tropical systems to affect the region, at least indirectly. While landfalls here are very uncommon, the main impact would be to dramatically enhance summer monsoonal activity over the desert Southwest, which could, paradoxically, increase flash flood risk and/or ignite wildfires via lightning strikes. Such events could also bring unusual summer or early fall thunderstorms to parts of California–either mitigating fire season there if associated with significant rainfall or otherwise accelerating if dry lightning and wind predominate.

Finally, the West Pacific outlook is less clear as the seasonal signals are not as pronounced as farther east or in the tropical Atlantic. That said, major El Niño years have in some cases historically been associated with a northward shift in the most likely TC landfall region as the genesis region shifts eastward into the Central (vs far West) Pacific before potentially recurving toward East Asia, perhaps increasing risk of landfall in or near Japan.

Ultimately, the convergence of a powerful El Niño and persistent global warming creates a potentially volatile risk landscape, where record-breaking temperatures and amplified hydroclimate extremes pose significant challenges through 2026 and beyond.