“Globally, May was 0.63°C warmer than the average May from 1981-2010, the warmest May in this data record” according to researchers at the EU’s Copernicus Climate Change Service (‘C3S’), implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission.  The last twelve-month period was close to 0.7°C warmer than average, matching the warmest twelve-month period.  Although May was colder than average for Europe, spring was 0.7°C above average.

Temperatures over Europe deviated quite substantially from the 1981-2010 average in May 2020.  They ranged from well above average over the south-west and far north-east of the continent, to well below average over a substantial region extending from Scandinavia to the Balkans and the northern coast of the Black Sea.  The average temperature over England was not exceptional, but, according to the UK’s Met Office, the country had its sunniest month and driest May on record.  Meanwhile, according to Meteo France, Brittany experienced its sunniest May and second sunniest month on record.

Outside Europe, temperatures were most above average over parts of Siberia, where they were up to 10°C above average.  They were also much above average over western Alaska, along the Andes bordering Chile and Argentina, and over regions in West and East Antarctica.  It was also much warmer than average over western North America, the far north and south of South America, north-western, central and south-western Africa, and south-eastern Asia.

Regions of below-average temperature include most of central and eastern Canada, the eastern USA, southern Brazil, parts of southern Asia, and Australia.  According to Australia’s Bureau of Metrology, it was the first month since October 2016 for which the national average temperature was below its 1961-1990 long-term average.

Although temperatures were a little below average over several regions in all major oceans, air temperatures over sea were predominantly higher than the 1981-2010 average.

Figure: Monthly global-mean and European-mean surface air temperature anomalies relative to 1981-2010, from January 1979 to May 2020 (note, the darker coloured bars denote May values). Data source: ERA5. Credit: C3S/ECMWF