El Niño in the equatorial Pacific has intensified rapidly and is now firmly established, with the WMO saying it is almost certain to persist through February 2027 and likely peak by year-end.
Sea surface temperatures in the Niño 3.4 region are already more than 2°C above average and could reach 3.6°C, potentially making this the strongest event in four decades.
El Niño conditions in the Equatorial Pacific Ocean strengthened rapidly over the past month or so, are firmly established and may strengthen further to peak around the end of 2026, according to the latest El Niño update from the World Meteorological Organization (WMO). The WMO, in a press briefing, also highlighted that there is a near 100 per cent probability of the El Niño event persisting through February 2027, a certainty in forecast which the United Nations’ weather and climate organisation has experienced for the first time.
El Niño is the warmer-than-normal phase of the El Niño Southern Oscillation (ENSO) phenomenon that mostly occurs in the eastern and central Equatorial Pacific Ocean due to slowing down or even reversal of trade winds over the region. El Niño is generally associated with warmer-than-normal global average temperatures and changes in rainfall patterns, both of which could lead to extreme weather events such as droughts, heat waves, wildfires and floods in different regions of the world.
“The widely used Niño 3.4 index, which measures sea surface temperature anomalies in central-eastern equatorial Pacific has strengthened markedly from an average +1.5°C above normal during May-July 2026 and +2.0°C above normal in July,” according to a WMO press release.
“Between late July and mid-August the sea surface temperatures were in the range of 2.2°C and 2.6°C above the average, which indicated the continued intensification. Forecasts show that the peak may go as high as 3.6°C above the average,” said Wilfran Moufouma-Okia, head of climate prediction services division at WMO, in the press briefing.
“This could be the strongest El Niño in the past four decades, when WMO started using the current indices for monitoring the strength of El Niño,” said Celeste Saulo, secretary general of the WMO, during a press briefing.
Warming is not confined to the surface but the sub surface is warming at unprecedented rate. “In some of the regions the sub surface temperatures were above normal by 8°C which is striking,” said Moufouma Okia. “Together, the surface and subsurface ocean conditions provide strong support for continued El Niño conditions and the potential for further strengthening during the coming months,” according to the WMO press release.
While WMO is almost certain about the El Niño continuing till February 2027 and mostly certain about it peaking by the end of the year the magnitude remains a little uncertain. The occurrence of El Niño increases the chances of major changes in temperatures, rainfall and atmospheric circulations around the world.
But the strength of the El Niño does not inform about the severity of the impacts in any given region. “Its effects vary according to location and season and can be modified by other climate drivers, including conditions in the Indian and Atlantic Oceans,” according to the press release.
For instance for South Asia and Australia, the Indian Ocean Dipole (IOD) is also an important factor that determines weather conditions. In the positive phase of the IOD, the western parts of the Indian Ocean are warmer-than-normal and the eastern parts are colder-than-normal. WMO expects a positive phase of IOD to develop between September and November which could counteract some of the impacts of El Niño over South Asia.
“Meanwhile, the equatorial Atlantic basin is forecast to remain generally warm, with SSTs in both the North and South Tropical Atlantic staying above normal. These conditions may reinforce, weaken or alter typical El Niño impacts in different regions,” said WMO in its press release.
WMO’s forecast for changes in rainfall patterns shows a typical El Niño response with chances of wetter than normal conditions in the Horn of Africa, some parts of central and southern South America. The prediction shows drier than normal conditions over the Indian subcontinent, Southeast Asia and the Maritime Continent, Australia, northern South America, Central America and the Caribbean.
“El Niño in Spanish means boy child – but it has the potential to deliver a massive blow to communities and economies across the world. We are already seeing disruption and devastation from droughts and floods and we expect these impacts to increase as El Niño intensifies,” said Saulo.
“This exceptional El Niño demands exceptional preparation and response. Never before in the 50-year history of the World Meteorological Organization have we launched such a major mobilization with National Meteorological and Hydrological Services who are on the frontline of delivering the forecasts and services to save lives and livelihoods,” Saulo added.