The World Meteorological Organisation (WMO) has warned that El Niño — the natural climate phenomenon that periodically warms surface waters in the central and eastern equatorial Pacific Ocean — has already set in and is forecast to develop rapidly into a strong event between July and September. The Geneva-based UN agency, which classifies El Niño events on a four-tier scale from weak to very strong, says this episode is on course to reach the third-highest level, with sea-surface temperature anomalies expected to exceed 2°C in key monitoring regions. Multiple leading global climate centres, using different models, show what the WMO describes as "remarkable agreement" on the outlook, giving forecasters high confidence in the assessment.

"El Niño conditions are already under way and are forecast to strengthen rapidly into a strong event," said WMO chief Celeste Saulo. "This will intensify the chances of drought and heavy rainfall and the risk of heatwaves on land and marine heatwaves in many regions." While El Niño typically peaks between November and February, its effects on global temperatures tend to register later. The agency predicts above-average temperatures across nearly all populated land areas outside the polar regions — broadly, between 60 degrees south and 60 degrees north latitude. Rainfall patterns will also shift significantly: above-normal precipitation is expected in parts of the southwestern United States, while the Indian subcontinent and much of Australia face drier-than-average conditions. In the northern hemisphere summer, El Niño's warm Pacific waters can also fuel hurricanes in the central and eastern Pacific while simultaneously suppressing storm development in the Atlantic.

The stakes are underscored by recent history. The previous El Niño contributed to making 2023 the second-hottest year on record, and 2024 the hottest ever at approximately 1.55°C above pre-industrial levels. The 2023–24 event, one of the five strongest ever recorded, also drove severe flooding in parts of South America. Climate scientists note that while there is no evidence El Niño is becoming more frequent or intense due to climate change, a warmer background ocean and atmosphere amplify the phenomenon's effects — providing more energy and moisture to fuel extreme weather. As one researcher put it, the current El Niño is "overlapped on an already warm ocean because of climate change," making associated impacts likely worse than they would otherwise be.

The WMO says it is scaling up early warning support, particularly for climate-sensitive sectors such as agriculture and public health. "Advanced seasonal forecasts and early warnings are vital to save lives and cushion the impact on our economies and our communities," Saulo said. For countries across the tropics and beyond, the message is clear: the window to prepare is now, before the event reaches its peak intensity later in the year.