The world's land and ocean surfaces averaged 16.35 C in August 2014, breaking the previous record set in 1998, reported the U.S. National Climatic Data Center run by the National Oceanic and Atmospheric Administration (NOAA).
The ocean was particularly warm, breaking a record high temperature set in June 2014 with an average global surface temperature of 17.11 C.
Looking at land temperatures only, this was the second-warmest August on record, after 1998.
August also topped off a record hot summer — the average temperature from June to August also beat out the previous record set in 1998 to be the hottest since 1880.
Overall, global surface temperatures in August were 0.75 C higher and those from June to August were 0.71 C higher than the average for the 20th century.
According to NOAA, nine of the 10 warmest Augusts on record have occurred during the 21st century. August 2014 was the 38th consecutive August with a temperature above the 20th century average.
Last year, the United Nations-sponsored Intergovernmental Panel on Climate Change reported that scientists could say with extreme confidence that human activity is the dominant cause of the global warming observed since the 1950s.
The higher temperatures are already linked to extreme weather such as heat waves, droughts, floods and rising sea levels. The UN has warned that could lead to increased risk of food shortages, disease outbreaks, financial costs and violence.
World leaders are meeting in New York on Sept. 23 for the next United Nations summit to discuss action to address climate change.