"With levels of Carbon dioxide in the atmosphere consistently breaking new records, the influence of human activities on the climate system has become more and more evident".
The WMO report has reported that heat records were broken across the globe, sea levels are up, and polar ice is reaching new lows.
The WMO said that extremes had continued into 2017.
Reports earlier this year from major scientific bodies included NASA, NOAA and the UK's Met Office which indicated that 2016 was the warmest year on record.
Less than three months into the year, climate changes around the world are continuing the record-breaking trends seen in 2016.
"This report confirms that the year 2016 was the warmest on record - a remarkable 1.1 (degrees Celsius) above the pre-industrial period, which is 0.06 (degrees Celsius) above the previous record set in 2015", Petteri Taalas, WMO secretary-general, said in a news release.
He said that even without a strong El Nino-a phenomenon that brings generally warmer temperatures every four to five years-2017 was "seeing other remarkable changes across the planet that are challenging our understanding of the climate system".
Each of the 16 years since 2001 has been at least 0.4 C above the long-term average for the 1961-1990 base period, used by WMO as a reference for climate change monitoring. Matthew Hurricane in the North Atlantic was one of the most damaging weather-related calamities, leaving hundreds of dead and swathes of destruction across Haiti.
WMO warned extreme weather and climate conditions have continued into 2017.
Changes in the Arctic and the melting of sea-ice are also leading to a shift in atmospheric circulation patterns impacting other parts of the world.
This year already saw temperature records continue to tumble, in the USA where February was exceptionally warm, and in Australia, where prolonged and extreme heat struck many states.
It is based on multiple worldwide datasets maintained independently by global climate analysis centres and information submitted by dozens of WMO Members National Meteorological and Hydrological Services and Research Institutes and is an authoritative source of reference. The new administration has coiled back some of the global warming measures taken by President Obama, while Scott Pruitt, the newly appointed head of the Environmental Protection Agency, denied that Carbon dioxide was a primary contributor to warming. The WMO said 2016 has continued warming trends that include a 0.1 to 0.2C increase per decade. "Instead, that heat went into the ocean, and we got much of it back again past year", said Dr Phil Williamson, from the University of East Anglia.
The lack of action from the U.S. will hamper efforts to tackle climate change, as it has the second-highest levels of emissions globally after China. "Those who dispute that link are not sceptics, but anti-science deniers".