Global temperatures in October, as well as the entire year-to-date, were the planet's hottest on average since record-keeping began in 1880.

It was also the 38th consecutive October in which global average temperatures were higher than the average for the 20th century, the National Oceanic and Atmospheric Administration (NOAA) reported.

"The January-October combined global land and ocean average surface temperature was the warmest such period on record, surpassing the previous record set in 1998 and 2010," NOAA said.

The combined average temperature over land and ocean surfaces in October was 14.74 degrees Celsius, which beat the previous record for the month by 0.01 degrees Celsius.

Warmer than average temperatures were recorded over most of the Earth's land surface, except for large parts of Central Asia.

"Record warmth was notable across a large area of southern South America, the US western coastal regions, Far East Russia, parts of southern and southeastern Asia, much of southern and western Australia, and parts of southern Europe," it said.

The average October temperatures globally over land alone were the month's fifth highest on record.

In the Arctic, the average extent of sea ice in October was the sixth smallest for the month since record-keeping began in 1979.

Antarctic sea ice also declined in October, ending a string of six consecutive months of increasing sea ice in the region.