"WMO does not expect the anticipated El Niño to be as powerful as the 2015-2016 event, but it will still have considerable impacts," the statement said.
The organisation 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.