NASA said it was the second-warmest year on record, while the National Oceanic and Atmospheric Administration said it was the third-warmest year.
Fresh data has revealed that "2015, 2016, and 2017 have been confirmed as the warmest years on record" the World Meteorological Organisation (WMO) has said.
But El Nino was not behind the warm temperatures in 2017.
An analysis of five worldwide datasets revealed that the global average surface temperature in 2017 was roughly 1.1C above the pre-industrial era.
Among extreme weather events past year, the Caribbean and the United States suffered a battering from hurricanes, the Arctic ended 2017 with the least sea ice for mid-winter and tropical coral reefs suffered from high water temperatures.
Figures from a series of different worldwide analyses show that, overall, 2017 was one of the three hottest years on record, with temperatures around 1.1C above pre-industrial levels.
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In addition to rising greenhouse gas levels in the atmosphere which is causing global warming, the climate also has naturally occuring phenomena which affect the surface temperature.
Both teams found that if it weren't for the El Nino climate pattern in 2017, it would have been the hottest year.
"However, 2017 is notable because the high temperatures continued despite the absence of El Nino and the onset of its cool counterpart, La Nina".
Professor Tim Osborn, director of research at the University of East Anglia's Climatic Research Unit added: "It isn't only the average global temperature that matters: we can also explain the geographical pattern of the warming".
WMO secretary-general Petteri Taalas said: "The long-term temperature trend is far more important than the ranking of individual years, and that trend is an upward one".
The result come in a big year for global climate diplomacy as countries seek to hew to the Paris climate goals of holding warming below 2 or perhaps 1.5 degrees Celsius above preindustrial levels. In the United States alone, weather and climate-related disasters cost the United States a record $306 billion in 2017, especially western wildfires and hurricanes Harvey, Maria and Irma, NOAA said last week.