In the spring of 1997, a pulse of warm water spread across the equatorial Pacific so fast that forecasters at NOAA scrambled to upgrade their outlooks month after month. By December, sea-surface temperatures in the benchmark Niño 3.4 region had spiked roughly 2.5°C above the long-term average, fueling catastrophic flooding from Peru to East Africa and drought-driven wildfires across Indonesia. Nearly two decades later, the 2015-16 El Niño matched that intensity, contributing to global coral bleaching, record heat, and billions of dollars in agricultural losses.
Now, as of June 2026, multiple independent U.S. climate models are projecting something potentially worse. Forecast systems inside NOAA are converging on a scenario in which Niño 3.4 anomalies could approach or exceed 3°C above average by late 2026 or early 2027. If that materializes, it would surpass both the 1997-98 and 2015-16 events and rank as the strongest El Niño in the modern observational record.
Where the forecasts stand right now
The strongest institutional signal comes from NOAA’s Climate Prediction Center, which issues monthly ENSO diagnostic discussions and accompanying probability tables. CPC’s spring 2026 outlook breaks projected outcomes into intensity bins for overlapping three-month seasons stretching into early 2027. The highest bin, covering Niño 3.4 anomalies at or above 2.0°C, defines what the agency classifies as a “very strong” El Niño. That bin now carries meaningful probability, a clear departure from the near-neutral conditions observed earlier in the year.
An independent check comes from NOAA’s Geophysical Fluid Dynamics Laboratory, which runs the SPEAR prediction system (Seamless System for Prediction and Earth System Research). SPEAR’s spring 2026 ensemble runs extend through early 2027 and can be compared against CPC’s North American Multi-Model Ensemble as well as the European Centre for Medium-Range Weather Forecasts. The upper end of SPEAR’s ensemble spread reaches into the 3°C range for Niño 3.4 anomalies, reinforcing the signal from CPC’s probability tables.
CPC uses the Relative Oceanic Niño Index, or RONI, to classify warm and cold episodes. RONI is calculated from ERSST version 5 anomalies using a 1991-2020 base period, with tropical-mean sea-surface temperature anomalies subtracted and the result variance-adjusted. That methodology strips out the background warming trend in tropical oceans, making it a cleaner gauge of genuine El Niño intensity than raw Niño 3.4 values alone. Under this framework, the agency’s latest outlooks show elevated odds of at least a strong El Niño developing by late 2026, with nontrivial probability extending into the very strong category.
Why 3°C is not a certainty
The 3°C figure sits at the upper edge of model spread, not at the center. CPC’s probability tables distribute likelihood across multiple intensity bins, and the very strong bin, while notable, does not dominate the total probability space. No official statement has confirmed that real-time buoy or satellite measurements already show 3°C anomalies. The number originates from model projections, not from observations taken to date.
GFDL labels its SPEAR seasonal predictions as experimental. That distinction carries weight. Experimental forecasts undergo peer review and validation, but they do not hold the same operational authority as CPC’s official outlooks. SPEAR’s track record at predicting extreme ENSO events, particularly those exceeding 2°C, has not been publicly benchmarked against a large sample of such rare occurrences. Scientists caution that individual ensemble members reaching 3°C should be read as plausible scenarios within a range, not as precise predictions.
Historical comparisons add another layer of difficulty. Research published in the Journal of Climate analyzing the 1877-78 El Niño using ERSSTv5 ensemble methods found that observational uncertainty is far larger in the 19th century. The study concluded that differences among major El Niño events may not be statistically significant once measurement error is accounted for. Even for well-observed events like 1997-98 and 2015-16, different indices can yield slightly different rankings depending on whether they emphasize central Pacific warmth, eastern Pacific warmth, or broader ocean-atmosphere coupling. A future event could set a record in one index while merely tying previous peaks in another.
What a super El Niño would mean on the ground
Neither CPC nor GFDL has published official estimates of agricultural losses, displacement, or infrastructure damage tied to a 3°C scenario. But the historical record offers a rough guide to the stakes.
During the 1997-98 event, flooding killed thousands of people in East Africa and Latin America, while drought and fires in Southeast Asia blanketed the region in haze and caused respiratory crises. Global grain markets tightened as harvests failed in Australia and parts of southern Africa. The 2015-16 El Niño contributed to severe drought in Ethiopia, food insecurity across Central America’s “dry corridor,” and record-breaking heat that pushed global average temperatures past 1°C above pre-industrial levels for the first time.
A stronger event would amplify those patterns, though the exact regional impacts depend on how long the warming persists and how it interacts with other climate drivers. A brief spike in sea-surface temperatures can produce different consequences than a prolonged multi-season event, even if both reach similar peak anomalies. For the United States, a strong El Niño typically brings a wetter-than-average winter across the southern tier of states, reduced Atlantic hurricane activity, and warmer conditions across the northern Plains and Great Lakes. Those tendencies would factor into water-management decisions, wildfire planning, and agricultural outlooks well before the event peaks.
How to track this as it develops
For anyone following this story, the evidence falls into three tiers worth keeping separate.
The first tier is CPC’s operational products: its monthly ENSO diagnostic discussion, probability tables, and RONI-based episode classification. These represent NOAA’s official position, are updated monthly, and include explicit descriptions of how forecasts are constructed and how confidence levels are assigned. They are the most authoritative public source.
The second tier includes experimental systems like GFDL SPEAR. These are scientifically rigorous and valuable as a cross-check. When multiple independent models point in the same direction, confidence in the general trajectory increases, even if exact magnitude and timing remain uncertain. When experimental systems diverge sharply from operational guidance, that gap is a signal to scrutinize model assumptions.
The third tier consists of secondary analyses that extrapolate from model outputs to predict specific regional disasters or dollar-figure losses. Those analyses may be directionally sound, but they lack the formal uncertainty quantification that primary agency products provide. When a headline claims a specific cost or death toll from a future El Niño, readers should trace the claim back to its source and check whether it rests on an official forecast or on inference.
For communities in flood-prone or drought-prone regions, the practical step now is to monitor CPC’s monthly updates and the seasonal outlooks from the National Weather Service, which translate raw Niño 3.4 projections into probabilistic maps of temperature, precipitation, and drought risk. Local emergency managers typically use those outlooks to guide decisions about reservoir levels, wildfire preparation, and flood readiness.
What the next few months will reveal
The most telling indicators between now and late 2026 will be the observed trajectory of sea-surface temperatures in the Niño 3.4 region, updates to CPC’s probability tables, and revisions to experimental forecasts as new ocean and atmosphere data are assimilated. If observations begin tracking the upper end of model projections, confidence in a very strong event will climb. If they lag behind, forecasters will revise expectations downward.
What the evidence supports today is straightforward: the odds of a strong El Niño emerging by late 2026 are elevated, and the possibility of a very strong event, one that could rival or exceed anything in the modern record, is real. The precise peak intensity, the ranking against past giants, and the detailed global consequences remain open questions. Preparing for a range of plausible outcomes, rather than locking onto a single number, is the most defensible position for policymakers, humanitarian agencies, and anyone living in a region where El Niño rewrites the weather.
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*This article was researched with the help of AI, with human editors creating the final content.
