By December, a 4.1°C Warm-Water Bubble Forms in the Pacific, Setting a New Temperature Record

A thermometer plunged into the heart of the tropical Pacific is driving scientists around the world into a frenzy. Beneath the ocean’s surface, a colossal mass of warm water is expanding week after week. The latest readings point to an anomaly that could exceed 4 °C above seasonal norms by December. Unprecedented since modern measurements began. This time, El Niño no longer plays by the same rules: meteorological agencies across the globe are already speaking of a historic episode, with consequences expected to reach far beyond the Pacific Ocean.

An unprecedented thermal anomaly is taking shape in the Pacific

The numbers speak for themselves. In the Niño 3.4 region, the reference benchmark for measuring this phenomenon, the sea surface temperature anomaly has risen from +1.6 °C in June to +2.5 °C in August. The World Meteorological Organization now projects an average of +3.7 °C for October-December. By comparison, the previous record, set during the 2015-2016 event, peaked at +2.6 °C. The latest projections go even further: an average peak around +4.2 °C above normal is expected in December in the central Pacific. That is higher than anything measured since records began in 1950. In other words, climate models have simply never had to cope with a configuration like this.

How this extreme Super El Niño forms and intensifies through December

This scenario does not rely on a single isolated source. Thirteen national and international centers cross their data from ocean buoys, satellites, and radiosondes to reach the same alarming conclusion. On the American side, NOAA estimates an 83% probability that El Niño will reach historical intensity between October and December. Probabilities even rise to 54% for September-November and drop slightly to 70% for November-January, evidence that the peak indeed lies at the end of the year. And the trend does not look set to reverse quickly: a strong to very strong episode remains plausible through January-March 2027, with a probability close to 100% that the phenomenon persists through February 2027 according to the WMO. The next official ENSO update is due on November 12, a milestone to watch closely to confirm or refine these forecasts. Another telltale sign: last August was the hottest August ever recorded on Earth. The record thermal anomaly expected for December confirms the formation of an event climatologists label as an Extreme Super El Niño.

What global weather disturbances this event will trigger this winter

The consequences will not be confined to the Pacific. The accumulated warm water acts as a driver that disrupts atmospheric circulation on a planetary scale. Excess rainfall already threatens the Horn of Africa, Central Asia, and California, with increased flood risks in these regions. Conversely, a severe rainfall deficit looms over the Indian subcontinent, southern Central America, and the Caribbean, where drought could become entrenched. For France and Europe, Meteo-France offers reassurance about the relative magnitude of the phenomenon: its influence, although statistically more pronounced in winter, remains well below the average impact of climate change on our territory. So it is not the cold snap or the heatwave that will determine the French winter, but the underlying climate dynamics already at work for several years.

This exceptional episode will intensify in the coming weeks. It is wise to keep a close watch on the forthcoming releases from the WMO and NOAA, especially the mid‑November update, to gauge the real extent of the upheavals to come. Droughts, floods, extreme heat: the signals are there, and they concern millions of people across several continents. Staying informed remains the best reflex to anticipate the concrete consequences of this extraordinary phenomenon.