GENEVA, Switzerland: The United Nations weather agency said on June 2 that a moderate or possibly strong El Niño could develop, which may raise global temperatures and increase the chances of extreme weather in the coming months.

El Niño is a regular pattern in which sea surface temperatures in the central and eastern Pacific Ocean become warmer than usual. It usually lasts about nine to 12 months, according to the World Meteorological Organization (WMO).

The WMO said that warming ocean waters are helping El Niño form and predicted higher-than-average temperatures in most parts of the world from June to August. It also said the event is likely to continue until November.

WMO Secretary-General Celeste Saulo warned that the world must prepare for a possibly strong El Niño, which could worsen droughts, bring heavier rainfall, and increase the risk of heatwaves both on land and in the oceans.

This weather pattern can disturb regional climates. It may lead to warmer conditions globally, while bringing more rain to southern South America, the southern United States, parts of the Horn of Africa, and central Asia. At the same time, it can cause drought in places like Australia, Central America, Indonesia, and parts of southern Asia, and may also trigger hurricanes in the central and eastern Pacific Ocean.

Saulo added that the last El Niño, from 2023 to 2024, helped make 2024 the hottest year ever recorded. She said extreme heat is already one of the most dangerous climate threats, and El Niño could make it even worse. This could lead to more heat-related illnesses, a wider spread of insect-borne diseases, and greater strain on food and water supplies. She also warned that communities already facing difficulties will be pushed even further.

The WMO observed changes in the Equatorial Pacific, where sea surface temperatures rose quickly from late April to mid-May, showing that El Niño conditions were developing. It also noted unusually warm temperatures beneath the ocean surface in the tropical Pacific, more than six degrees Celsius above normal, creating a heat buildup that is warming the surface.

Some national weather agencies have warned that this could be the strongest El Niño in a decade, with hotter and drier weather expected across Asia in the second half of 2026. This could harm crops and food supplies, especially as farmers are already dealing with fertilizer shortages and expensive fuel linked to the war in Iran. However, the WMO said there is still uncertainty, as some forecasts do not show a strong El Niño.

U.N. Secretary-General António Guterres said the world must treat this as an urgent climate warning, adding that El Niño will exacerbate global warming. He called for moving away from fossil fuels and switching to renewable energy.

The WMO also said that while climate change does not appear to increase the frequency or intensity of El Niño events, it can make their effects, such as extreme heat and heavy rainfall, more severe.