The year 2017 will likely be among the three warmest years on global record, according to the World Meteorological Organization (WMO).
The first 11 months of 2017 were the third warmest on record, behind 2016 and 2015, with much-warmer-than-average conditions engulfing much of the world's land and ocean surfaces, researchers said.
Arctic and Antarctic sea ice coverage remain at near record lows.
2017 may also be the warmest year without an El Nino - a climate phenomenon that causes global temperatures to shoot up.
Data from NASA and the European Centre for Medium Range Weather Forecasts (ECMWF) shows that the past meteorological year (December 2016 to November 2017) is the second warmest on record.
"What is more important than the ranking of an individual year is the overall, long-term trend of warming since the late 1970s, and especially this century," said Omar Baddour, senior scientist at WMO.
"Along with rising temperatures, we are seeing more extreme weather with huge socio-economic impacts," Baddour said.
WMO will combine datasets from US National Oceanic and Atmospheric Administration (NOAA), NASA's Goddard Institute for Space Studies (GISS), and the Met Office Hadley Centre and Climatic Research Unit in the UK for a consolidated temperature ranking for 2017.
According to NOAA, the month of November was the fifth warmest on record, whilst NASA and ECMWF Copernicus Climate Change Service both said it was the third warmest.
During November 2017, warmer-than-average temperatures dominated across much of the world's land and ocean surfaces, with the most notable temperature departures from average across the Northern Hemisphere.
Parts of the western contiguous US, northern Canada, northern and western Alaska, western Asia and Far Eastern Russia had temperature departures from average that were 2.0 degrees Celsius or greater, according to NOAA.
As an indication of swift regional climate change in and near the Arctic, the average temperature observed at the weather station has now changed so rapidly that it triggered an algorithm designed to detect artificial changes in a station's instrumentation or environment and disqualified itself from the NCEI Alaskan temperature analysis.
The omission was noticed by the National Centers for Environmental Information (NCEI), which realised that data from Reykjavik, Alaska had been missing for all of 2017 and the last few months of 2016.
Elsewhere in the Arctic, a separate analysis from the EMF Copernicus Climate Change service said that November's temperature was more than six degrees Celsius above average in parts of Svalbard, as it was in October.