An El Nino event is likely by the end of the year, the UN said Monday, and the weather pattern could disrupt what has already been a hot year.
The World Meteorological Organization forecast "a 70 percent chance of an El Nino developing by the end of this year," a WMO statement said.
El Nino is triggered by periodic warming in the eastern Pacific Ocean which can trigger drought in some regions, heavy rain in others.
"WMO does not expect the anticipated El Nino to be as powerful as the 2015-2016 event, but it will still have considerable impacts," the statement said.
The organization sees increased odds of higher surface temperatures in most of Asia-Pacific, Europe, North America, Africa and along much of South America's coastline.
Interior parts of South America, Greenland, many south Pacific islands and some in the Caribbean were identified as possible exceptions.
WMO Secretary-General Petteri Taalas noted that 2018 "is on track to be one of the warmest on record," after especially high temperatures in July and August across several parts of the world.