Last month was the world's hottest September since record-keeping began in 1880 the United States National Oceanic and Atmospheric Administration (NOAA) says.
It also marked the 38th consecutive September with a global temperature above the 20th century average the NOAA said.
When combining average temperature over land and ocean surfaces, NOAA found a record high for September at 15.72 degrees Celsius, or 0.72 degrees Celcius above the 20th century average.
"With the exception of February, every month to date in 2014 has been among its four warmest on record, with May, June, August and September all record warm," said the NOAA report.
It said most of the land on Earth was warmer than normal last month, except for central Russia, some areas in eastern and northern Canada, and a small region in Namibia.
"Record warmth was notable in much of northwestern Africa, coastal regions of southeastern South America, southwestern Australia, parts of the Middle East, and regions of southeastern Asia," the report said.
When it came to the world's oceans, the September global sea surface temperature was 0.66C above the 20th century average, the highest on record for September.
The report showed September marked the highest departure from average for any month since records began in 1880, breaking the previous record of 0.65C set just one month earlier in August
It said record warmth was observed in parts of every major ocean basin, particularly in the northeastern and equatorial Pacific Ocean.