El Niño is a periodic warming of sea surface temperatures in the central and eastern Pacific Ocean, which typically lasts between nine and ​12 months, according to the World Meteorological Organisation.

The WMO said warm ocean waters were ​fueling El Niño’s development and predicted above-average temperatures in most parts of ⁠the world from June to August.

The WMO said it is likely El Niño will ​continue until November.

“We need to prepare for a potentially strong El Niño event — which will exacerbate ​drought and heavy rainfall and increase the risk of heatwaves both on land and in the ocean,“ said WMO Secretary-General Celeste Saulo.

The most recent El Niño, in 2023-24, contributed to 2024 being the hottest year on record, ​Saulo added.

A shift has been observed in the Equatorial Pacific, with sea surface temperatures rising ​rapidly from late April to mid-May, suggesting El Niño conditions were developing, the WMO said.

The agency said ‌it has ⁠observed unusually warm subsurface conditions across the tropical Pacific with temperatures exceeding 6 degrees Celsius above average, creating a reservoir of heat that is driving surface warming.

The weather pattern is known to disrupt regional climates, potentially bringing increased rainfall to southern South America, the southern United States, ​parts of the Horn ​of Africa and central ⁠Asia, while causing drought in Australia, central America, Indonesia, and sections of southern Asia.

It can also have a warming effect on the global ​climate and fuel hurricanes in the central and eastern Pacific Ocean, ​the WMO said.

“The ⁠world must treat it as the urgent climate warning it is. El Niño conditions will pour fuel on the fire of a warming world,” said UN Secretary-General António Guterres, urging a shift away ⁠from ​fossil fuels towards renewable energy.

While there is no evidence that ​climate change increases the frequency or intensity of El Niño events, it can make associated impacts such as extreme heatwaves ​and heavy rainfall worse, according to the WMO.