Super El Niño sea temperatures have reached record levels weeks before the expected December peak, with Australia’s Bureau of Meteorology saying average weekly sea-surface temperatures in the central Pacific are now the highest on record. Zeke Hausfather, a climate scientist at Berkeley Earth, said: “We are currently witnessing an El Niño event that is unprecedented in the historical record,”
He also said: “The strength of El Niño this year is spilling out of the traditional El Niño region,” a shift that matters because the warmth now extends beyond the equatorial Pacific zone usually used to track the event. Australian and US forecasters are comparing the pattern with earlier episodes using the Relative Ocean El Niño Index, or RONI, to strip out some of the extra ocean warming that can blur the signal.
Pacific records and the 2015 benchmark
Scientists said a new daily sea surface temperature record was set in the central-eastern Pacific in September, beating the previous mark from 2015, the very strong El Niño that had stood as the benchmark. The Bureau of Meteorology’s average weekly data, which go back to 2008, now exceed levels seen in December of 2015, and temperatures above 30C have been recorded for the first time in parts of the tropical Pacific.
Those readings sit inside the region forecasters monitor for El Niño, where record sea-surface temperature anomalies and exceptional subsurface warmth have both appeared. El Niño typically comes around every two to seven years and lasts for around a year, but the current cycle is pushing past the pattern forecasters expected when they first compared it with the historical record.
Beyond the tropical Pacific
The warmth is not staying in one lane. Comparisons with 1972-73, 1982-83, 1997-98 and 2015-16 show more widespread ocean heat across the Pacific and into the Gulf of Mexico than in those earlier events, which is why forecasters are leaning on RONI rather than raw sea-surface readings alone.
That wider footprint came as Hurricane Polo reached Puerto San Carlos, Baja California Sur, Mexico, on 29 September, with flooded streets shown after the arrival of a Category 3 storm. The overlap with an already busy hurricane season gives forecasters a moving target: how much of the current record warmth belongs to El Niño itself, and how much reflects the long-term warming of the Pacific that can mask the natural signal.
What forecasters are watching
The next shift is the December peak that scientists expect, with the open question centered on whether the current record can climb much further before then. For readers following the Pacific, the immediate marker is not another calendar date but whether the record heat keeps spreading beyond the traditional El Niño region and into waters that are already feeding storms.
