Globally, September 2021 was one of the four warmest Septembers, for the reference period 1991-2020, along with those of 2020, 2019 and 2016.
In Europe, temperatures were warmer than the 1991-2020 average over most of central, southern and western regions. The French national meteorological service (Météo-France) reported the highest daily maximum September temperature for the whole country, while in the United Kingdom, the second warmest September on record was reported by the UK Met Office.
September was warmer than average over most of other land masses, as high temperatures were recorded over central regions of the USA and Canada, north-western Africa, an arc from Iran through central Asia to south-eastern China, most of Siberia, drought-hit central South America (as highlighted by the JRC-GDO report), and much of the Antarctic (with the exception of West Antarctica).
Colder than average temperatures occurred in a region extending eastward from eastern Europe to central Russia, including most of Kazakhstan. Other regions with below-average temperatures include Alaska, Greenland (with the exception of north-eastern areas), northern Brazil, northeastern Africa, parts of north-western India and south-western China, the easternmost Russia, as well as most of Australia