The global record set in December 2015 was also matched, says the EU's climate change monitoring agency.
The European Union's climate change monitoring agency, Copernicus, has reported that temperatures across Europe in December 2019 were the hottest on record for that month.
Data shows the average surface air temperature over Europe was 3.2°C warmer than the standard reference period for December for 1981-2010.
Global temperatures also peaked near the record level set in December 2015.
Meanwhile, data also shows that 2019 was the second warmest year recorded, at 0.59°C above average.
Copernicus says that the five warmest years on record have all occurred in the last five years, with 2019 coming in as the second warmest and the period 2010-2019 being the warmest decade on record.
The results are in line with previous projections from the World Meteorological Organisation and the Global Carbon Project, as atmospheric carbon dioxide concentrations continue to increase.
Jean-Noël Thépaut, director of ECMWF Copernicus, said that "these are unquestionably alarming signs".
A more detailed analysis of the climate in Europe will be presented by Copernicus in its European State of the Climate 2019, which is set to be released in April.