In the central equatorial Pacific, daily temperature readings are now exceeding previous highs by a large margin; senior climatologist Felicity Gamble of the Bureau of Meteorology said the rate of warming over the past six months is the fastest ever documented.

The strength of an El Niño is quantified with the Niño3.4 index, which removes the long‑term warming trend to isolate the event itself. Models indicate the index will top 2.6 °C this month and could reach 3.6 °C, a value that would surpass the 1983 benchmark that, despite a 2.65 °C reading in 1902, is regarded as the strongest El Niño in living memory because of more reliable data.

Scientists link much of this exceptional intensity to climate‑change‑driven ocean heating. Andrew Watkins, an adjunct professor and climate councillor at Monash University, explained that roughly 90 % of the excess heat trapped in the atmosphere is transferred into the oceans, which in turn fuels El Niño and La Niña cycles.

Nevertheless, scientists caution that the precise mechanisms behind this year’s record‑breaking behavior are not fully resolved; while the unprecedented warming provides a plausible contribution, the interplay of oceanic and atmospheric processes remains complex and partly uncertain.

The convergence of unprecedented Pacific warming, a soaring Niño3.4 index, and the massive oceanic heat uptake underscores why this El Niño is poised to become the strongest on record, highlighting the growing influence of a warming climate on natural climate variability.