UN News: WMO Puts El Niño Persistence Through February 2027 Near 100%

El Niño is strengthening rapidly in the Pacific and has not yet peaked, according to a UN News report published on 3 September 2026 summarising new forecasts from the World Meteorological Organization (WMO). The UN weather agency now puts the likelihood that the event persists through February 2027 at close to 100 per cent — a level of confidence UN News says the agency has never before attached to a forecast for El Niño or its cooler counterpart, La Niña.

The WMO expects the event to become "very strong" and to peak around the end of the year, UN News reports. Because the pattern is already firmly established and still building, the agency's outlook points to months of unusual warmth, along with flooding in some regions and drought in others.

The numbers behind the forecast

The Niño 3.4 index, which tracks ocean temperatures in the central tropical Pacific, averaged 1.5°C above normal from May through July, according to figures relayed by UN News. By July the index had reached 2°C, and weekly readings from late July through mid-August climbed as high as 2.6°C.

The warmth is not confined to the surface. UN News describes a large reservoir of unusually warm water below the tropical Pacific that could continue to feed the event: in some parts of the basin, subsurface temperatures in July and early August ran more than eight degrees Celsius — around 14 degrees Fahrenheit — above normal. That depth of heat, the report says, indicates the warming is not fleeting and that El Niño still has considerable fuel available.

UN News notes that El Niño is a naturally occurring pattern that typically develops every two to seven years, when waters in the central and eastern equatorial Pacific turn unusually warm, altering atmospheric circulation and shifting rainfall and temperature far from the Pacific itself. What is unusual this time, the report adds, is the backdrop: oceans that are already exceptionally warm provide a hotter baseline for the cycle. UN News is explicit that scientists have not established that human-caused climate change is increasing or intensifying El Niño, while noting that a warmer atmosphere and ocean can amplify some of its consequences by adding heat and moisture available to extreme weather.

Uneven impacts, overlapping patterns

A very strong El Niño does not mean every region will see disasters of the same magnitude, UN News cautions. From September through November, however, forecasters expect above-normal temperatures across nearly the entire surface of the Earth, with rainfall patterns taking on the characteristic El Niño signature — raised chances of heavy rain and flooding in some places, drought in others.

Two other large-scale features could complicate the picture. A positive phase of the Indian Ocean Dipole is expected to develop, and the tropical Atlantic is forecast to remain unusually warm. Those overlapping influences, UN News says, make it impossible to translate El Niño's strength into a precise forecast for any individual country, though collectively the signals point to heightened risk.

Warnings from the UN

"El Niño is being supersized before our eyes," UN Secretary-General António Guterres said in a press release quoted by UN News. "The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up."

WMO chief Celeste Saulo framed the stakes in similar terms: "El Niño means 'little boy' in Spanish, but it has the potential to deliver a massive blow to communities and economies around the world." She added that droughts and floods are already causing disruption and devastation, and that the agency expects those impacts to worsen as the event intensifies.

The forecast has triggered what UN News calls a first-of-its-kind mobilisation with national weather agencies, aimed at strengthening forecasts and early-warning systems. The effort is intended to help governments and humanitarian organisations prepare for effects on vulnerable sectors including agriculture, public health, energy and water supplies. "This exceptional El Niño demands exceptional preparedness and response," Saulo said.

For background on how the indices in this report are defined, see our science and glossary pages.