Sea surface temperatures suggest El Niño is strengthening

Sea surface temperatures in the central and eastern tropical Pacific are set to soar to record highs during October to December 2026, signifying the intensification of the El Niño phenomenon. This could have far-reaching impacts on weather patterns, economies, ecosystems, and communities worldwide. The World Meteorological Organization (WMO) states that the El Niño is expected to intensify and reach its peak in December.

The organization predicts that it may become one of the strongest events since at least 1950, with a nearly 100% chance of persisting through February 2027. El Niño works by releasing stored heat from the ocean depths, which led to the record-breaking global temperatures in 2024. The warmth lies in the warmest ocean conditions ever recorded.

Niño 3.4 sea surface temperature anomalies, a critical metric, have risen from +1.6°C above normal in June 2026 to +2.5°C in August, and are forecast to peak around +3.7°C in October to December, surpassing the previous record of +2.6°C set in 2015-2016. Other ocean regions are also contributing to the forecast. A positive Indian Ocean Dipole, which can significantly influence regional rainfall, is expected to reach its peak in October and then diminish.

The seasonal anomaly is anticipated to hover around +0.5°C. Meanwhile, sea temperatures in the equatorial Atlantic basin are projected to stay above average. Global records were smashed in August with the hottest temperature ever observed, according to reports from the European Union's Copernicus Climate Service, the U.S. National Oceanic and Atmospheric Administration, and NASA.

The Global Seasonal Climate Update indicates a high probability of above-average temperatures across major regions in October to December, although this does not guarantee that every location will be warmer than average each day. Instead, it signals a strong seasonal trend indicating a heightened likelihood of heat extremes and associated impacts.

The update also projects substantial shifts in rainfall patterns, as expected in a robust El Niño event. Regions to anticipate above-normal rainfall include the central and eastern equatorial Pacific east of the international date line, the Greater Horn of Africa, parts of Central Asia and coastal East Asia, northern areas of the Arabian Peninsula, sections of North America south of 45°N, and southeastern South America.

Conversely, a dry signal is expected over the western Pacific and equatorial Atlantic, spanning the South Pacific to southern South America, and the Indian subcontinent, southern Central America, parts of the Caribbean, and northwestern South America.