"The year-to-date (January-October) global temperature remained the highest on record," said the monthly report from the National Oceanic and Atmospheric Administration (NOAA).
This follows the record-shattering heat years of 2014 and 2015.
Experts say 2016 is likely to become the hottest year on record due to the continued burning of fossil fuels that contributes to global warming, and exacerbated by the ocean warming trend of El Nino, which formally ended in July.
"For the year to date, we are record warm for 2016," Jessica Blunden, climate scientist at NOAA National Centers for Environmental Information, told reporters on a conference call.
"It is likely that 2016 will still pass 2015 as the warmest year on record," she said, even though temperatures may cool in the months ahead due to the La Nina weather phenomenon.
"Even if we don't, 2016, 2015 and 2014, however they stack up, are going to be the three warmest years in the historical record which dates back to 1880."
So far, the year-to-date temperature across global land and ocean surfaces is 1.75 Fahrenheit (0.97 Celsius) above the 20th century average, NOAA said.
Taking October alone, scientists found the global average for temperature "tied with 2003 as the third highest for the month of October in the NOAA global temperature dataset record, which dates back to 1880."
The month's average global land and ocean surface temperature was 1.31 Fahrenheit above the 20th century average of 57.1 Fahrenheit.
It was slightly cooler than the record-setting October of last year, when El Nino was strengthening, leading to higher temperatures in the equatorial Pacific and beyond.
This year, La Nina conditions prevailed in October, causing below-average temperatures across the eastern tropical Pacific Ocean.
