Let's be precise about terminology first. "Super El Niño" is not an official category. The World Meteorological Organization states that the term is not part of its operational classification system and is not used in official WMO products, and NOAA's Climate Prediction Center uses weak, moderate, strong and very strong instead. Very strong means a three-month RONI value at or above +2.0°C, and that band is open-ended, so there is no separate official tier above it.
The informal term is not meaningless, but it is inconsistently defined: competing definitions in circulation use different thresholds, different indices, and in at least one case a bespoke composite score rather than a temperature at all. That is why this article does not attempt to list which past events were "true" Super El Niños. Any such list depends entirely on which index and threshold you pick, and a list drawn up on the conventional ONI does not survive translation to RONI. The full vocabulary is set out in "Super El Niño" is not an official WMO or NOAA category.
Why Forecasters Are This Confident, This Early
Normally, June sits inside what climatologists call the Spring Predictability Barrier, a stretch where ENSO forecasts are historically unreliable because the ocean-atmosphere system is in transition. Models that are confident in June have, in past years, often been wrong by August.
What's different this time is the subsurface signal. A large, well-organized downwelling Kelvin wave, essentially a slow-moving pulse of warm water below the surface, has been propagating east across the equatorial Pacific for weeks, with subsurface anomalies reported as high as +8°C at 50–250m depth. That's running warmer than the equivalent stage of the 1997–98 event, which is the closest thing the modern record has to today's setup.
NASA's Sentinel-6 Michael Freilich satellite, which measures sea surface height (a proxy for subsurface heat, warmer water expands and the surface literally rises), shows a pattern in the western Pacific on June 8 that JPL scientists described as visually similar to 1997 at the same point in the year. The eastern Pacific, however, is lagging behind 1997's pace, fewer Kelvin waves have arrived there so far. Whether this event "catches up" to 1997's trajectory is still an open question.
"For now, it looks like it's going to be a big one, more so than I would have said last week, but we still need more observations to know what's going to happen."
Severine Fournier, NASA JPL, Sentinel-6 deputy project scientistHow the Models Compare
What's notable isn't any single model, it's that NOAA's CFSv2, the European ECMWF, and Australia's BOM are now converging on the same outcome, which historically has been a stronger confidence signal than any one center's forecast alone.
| Source | Forecast | Confidence Trend |
|---|---|---|
| NOAA CPC | 63% chance "very strong" by NDJ 2026-27 | Watch → Advisory (June 11) |
| ECMWF | ~100% probability of "super" threshold | 22% (Mar) → 80% (Apr) → ~100% (May) |
| CSU Hurricane Team | Hurricane forecast cut to 11 named storms | Down from 13, cited directly to El Niño shear |
| IRI/Columbia | 98% probability El Niño persists through early 2027 | Up from 82% two weeks prior |
That rate of escalation, particularly ECMWF's jump from 22% to effectively 100% probability in under two months, is itself unusual. Forecasters have explicitly noted it's a steeper buildup than the lead-up to either 1997–98 or 2015–16.
Why This Matters Beyond the Headlines
A strong El Niño isn't just an ocean curiosity, it reorganizes global weather for 6–12 months and reliably nudges global average temperature upward on top of the existing human-caused warming trend, since the two effects are additive rather than competing. Scientists have described El Niño as acting like a temporary "mini global warming" event: it releases heat that's been stored in the deep ocean for years and dumps it into the atmosphere, where it raises surface temperatures for the duration of the event before the ocean re-absorbs heat during the following La Niña or neutral phase.
The practical, near-term effects already visible: the 2026 Atlantic hurricane season has opened unusually quiet, with El Niño's increased upper-level wind shear suppressing storm formation before the season even got going, CSU's most recent outlook reflects that directly. On the flip side, the eastern and central Pacific hurricane basin tends to get more active under El Niño, which is consistent with what's been observed so far this year.
The Honest Uncertainty
None of this is locked in. NOAA's own language is careful to note "substantial uncertainty in the peak strength," and the gap between the eastern Pacific's slower warming and the western Pacific's 1997-like signal is a real open question, not a rounding error. A 63% probability of "very strong" also means there's a real chance, roughly 1 in 3, that this event peaks at merely "strong," which would still be a significant event, just not a historic one.
What we can say with more confidence: this site's own RONI tracker and SST spaghetti chart are already showing this year's trajectory running well above both the 1997 and 2015 analog lines at the same point in the calendar, which is exactly the kind of real-time confirmation that's been feeding the "Super El Niño" headlines. We'll keep updating as the weekly CPC data comes in.