WMO: El Niño Has Developed and Could Strengthen Rapidly, Raising Odds of Heatwaves and Drought

The World Meteorological Organization warned Friday that El Niño has developed in the tropical Pacific and is expected to strengthen quickly in the coming months, raising the global odds of heat waves, drought in some places and heavier rainfall in others. The main message from forecasters is not only that El Niño has arrived, but that several major forecasting centers now broadly agree it could become a strong event later this year.

In its monthly Global Seasonal Climate Update, the U.N. weather agency said El Niño is forecast to develop rapidly into a strong event during July through September 2026. WMO said multi-model forecasts show seasonal average sea-surface temperature anomalies above 2 degrees Celsius in key central and eastern equatorial Pacific regions. El Niño typically peaks between November and February, and the latest models suggest additional strengthening into Northern Hemisphere autumn.

“El Niño conditions are already underway and are forecast to strengthen rapidly into a strong event … This will intensify the chances of drought and heavy rainfall and the risk of heatwaves on land and marine heatwaves in many regions of the world,” WMO Secretary-General Celeste Saulo said in a press release Friday. WMO said the event will increase the likelihood of extremes across many regions, while emphasizing that the exact effects will vary from place to place.

The WMO outlook aligns with other major forecasting centers. The U.S. National Oceanic and Atmospheric Administration’s Climate Prediction Center issued an El Niño Watch on May 14 and said El Niño was likely to emerge soon, with an 82% chance in May through July 2026, and to continue through Northern Hemisphere winter 2026-27, with a 96% chance in December through February. The International Research Institute for Climate and Society said June 22 that “the latest weekly Niño 3.4 index, centered on June 17, 2026, climbed further to +1.7 °C,” and that ocean and atmosphere signals were increasingly lining up with El Niño conditions. In Europe, Copernicus and the European Centre for Medium-Range Weather Forecasts said seasonal forecasts in June also pointed to a strong event, with 75% of grand ensemble members exceeding 2.5 C in the Niño 3.4 index by November.

El Niño is the warm phase of the El Niño-Southern Oscillation, or ENSO, a recurring climate pattern centered in the tropical Pacific. Changes in Pacific Ocean temperatures can alter wind, rainfall and storm patterns far beyond the region. El Niño is often associated with drier conditions in Australia, Indonesia and parts of Southeast Asia, and wetter conditions in parts of the southwestern United States and southern South America, though outcomes depend heavily on timing and location.

The U.N. is already preparing. WMO said it has launched “an unprecedented mobilization” to coordinate activity across the United Nations system and regional partners, and said it had already briefed U.N. agencies and humanitarian partners, including at a coordination briefing on June 24. One practical consequence is already showing up in forecasts elsewhere: NOAA’s 2026 Atlantic hurricane outlook cited expected El Niño conditions as one reason for predicting a below-average Atlantic hurricane season, while El Niño typically favors more cyclone activity in the eastern and central Pacific. As additional background, Copernicus said daily global sea-surface temperatures set records for the time of year in late June, reflecting both the onset of El Niño and longer-term warming.

Even with broad agreement that El Niño is strengthening, WMO stressed that the phenomenon shifts the probabilities of extreme weather rather than guaranteeing specific outcomes. Local impacts will depend on the event’s intensity, timing and duration, as well as how it interacts with other climate patterns.