September 2020 was the warmest September on record

Globally and in Europe, September 2020 was the warmest September on record, with the global average 0.05°C warmer than the previous warmest September in 2019. Temperatures were well above average in many regions across the globe, including off the coast of northern Siberia, in the middle East, in parts of South America and Australia. Cooler than average conditions marked the eastern equatorial Pacific Ocean, consistent with the ongoing La Niña event.

Surface air temperature anomaly for September 2020 relative to the September average for the period 1981-2010. Data source: ERA5. Credit: Copernicus Climate Change Service/ECMWF.

Global-mean temperatures were substantially above average in September  2020. The month was:

• 0.63°C warmer than the 1981-2010 average for September
• the warmest September in this data record
• warmer by 0.05°C than September 2019, the previous warmest September
• warmer by 0.08°C than September 2016, the third warmest September.

Monthly global-mean and European-mean surface air temperature anomalies relative to 1981-2010, from January 1979 to September 2020. The darker coloured bars denote the September values. Data source: ERA5. Credit: Copernicus Climate Change Service/ECMWF.

European-average temperature anomalies are generally larger and more variable than global anomalies. The European-average temperature for September 2020 was: 

• the highest on record for September
• 1.8°C above the 1981-2010 average
• 0.2°C above the value for September 2018, the previous warmest September.

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See also

_{^{Sea ice cover for September 2020}}

Arctic sea ice saw its second lowest September average extent on record, more than 40% below the 1981-2020 average.