It was the warmest September on record for the globe. The first nine months of 2020 were the second warmest on record (after 2016), according to the U.S. National Oceanic and Atmospheric Administration (NOAA).
The 10 warmest Septembers have all occurred since 2005. The seven warmest Septembers have occurred in the last seven years (2014-2020), continuing the long-term warming trend.
The Southern Hemisphere’s land and ocean surface temperature departure from average for September 2020 was the highest on record. Meanwhile, the Northern Hemisphere had its third-warmest September on record. Arctic sea ice extent was the second lowest on record, whilst Antarctic sea ice was above average.