If 1997-98 is the classic textbook Super El Niño, 2015-16 — nicknamed the "Godzilla El Niño" by some forecasters at the time — is the modern record-holder. It remains, per NOAA's own data, the strongest El Niño event since reliable record-keeping began in 1950.
Similarities to 2026
Like the current event, 2015-16 built on top of an already-warming global ocean, and like 2026, model ensembles converged on a "very strong" classification well before the event actually peaked — though forecasters at the time noted the convergence happened somewhat later in the year than what's being seen now. Both events also featured a strong subsurface heat signal months ahead of the surface peak, the same kind of Kelvin wave buildup currently being tracked in the equatorial Pacific.
Where They Diverge
One notable difference: 2015-16 developed more gradually through the year, with its most dramatic ECMWF probability jumps coming later in the season than what's been observed in 2026's faster-moving forecast escalation. If that pace continues, 2026 could either be on track to match or exceed 2015-16's strength — or the extra speed could mean an earlier peak and earlier decay. Both are plausible outcomes at this stage, and it's exactly the kind of detail the next few CPC monthly updates should start to clarify.
Also worth remembering: 2015-16's regional impacts weren't uniform even within a single strongly-correlated region — Southern California got the expected wet winter, but Northern California's rainy season underperformed expectations, a reminder that "strong El Niño" doesn't mean "guaranteed outcome everywhere," even in the most reliable corner cases.