The El Niño weather pattern has grown stronger over the last month and is expected to be one of the strongest on record during its peak between October and December, US forecasters said.

The US Climate Prediction Center (CPC), in its latest update, indicated that there was an 81% risk of a very strong El Niño event (two degrees Celsius or more above an index value) during the October to December season, which would be one of the biggest events in the historical record since 1950. The CPC also assigned a 97% probability of the event continuing into early spring 2027.

The sea surface temperature in the Niño 3.4 region is now 1.2°C above average. In addition to the warming waters developing below the surface, the ocean-atmosphere system is also showing signs of a strengthening El Niño, including changing wind and pressure patterns, the CPC said.

The forecast follows an earlier one by El Niño specialist Tim Stockdale at the European Centre for Medium-Range Weather Forecasts, who stated it would be "a very, very big surprise" if it did not turn out to be a record-breaker.

El Niño raises sea surface temperatures over the central and eastern equatorial Pacific, affecting circulation patterns around the globe through changes in winds, atmospheric pressure and rainfall. The knock-on effects generally include drought and drier conditions in Australia, wetter winters in East Africa and the southern United States, and indications of colder conditions later in winter in northern Europe.

Climate scientist Isla Simpson of the US National Center for Atmospheric Research pointed out that global warming appears to make El Niño more extreme, with more intense El Niño and La Niña events. In addition to human-induced climate change, the previous El Niño helped make 2023 the second warmest year and 2024 the hottest year ever recorded, raising fears about what the current record-breaking event may bring in terms of global temperatures.