Average temperatures were more than 2°C above normal and it has become the hottest June ever recorded.

Although not as persistent as that of summer 2018, this short heat wave, caused by a mass of hot air coming from the Sahara Desert, was intense.

The five days of unusually high temperatures followed days with record-breaking temperatures further east in Europe, Copernicus Climate Change Service website said.

This led to the month as a whole being around 1°C above the previous record for June, set in 1999, and about 1°C higher than expected from the trend in recent decades.

Data provided by the Copernicus Climate Change Service (C3S), implemented by the European Centre for Medium-Range Weather Forecasts on behalf of the European Union, show that the global-average temperature for June 2019 was also the highest on record for the month. It was about 0.1°C higher than that of the previous warmest June, in 2016, following a strong El Niño event.

The map of temperature anomalies shown above, based on the latest C3S data, highlights just how unseasonably warm the end of the month was. Compared to the average for the same five days during 1981-2010 (the standard 30-year climatological reference period), temperatures of 6-10°C above normal occurred over most of France and Germany, northern Spain, northern Italy, Switzerland, Austria, and the Czech Republic, Copernicus Climate Change Service website said.

Although it is difficult to directly attribute this heat wave to climate change, such extreme weather events are expected to become more common as the planet continues to warm under increasing greenhouse gas concentrations.

Looking at the temperature data from a longer-term perspective reveals the month to be even more unusual. Merging the latest C3S data with datasets that extend further back in time shows that the June 2019 European-average temperature was more than 3°C higher than the average for 1850-1900.

Spikes in European-average June temperature of more than 1°C above normal have occurred several times during the last 150 years; in 1901 and 1917, as well as 1999, for example. The temperature in June 2019 was exceptional because its spike came on top of a general rise of around 1.5°C or more in European temperature over the past one hundred years. This rise in European temperature is notably higher than that of around 1°C seen globally.

Jean-Noël Thépaut, Head of C3S, comments: “Although local temperatures may have been lower or higher than those forecast, our data show that the temperatures over the southwestern region of Europe during the last week of June were unusually high. Although this was exceptional, we are likely to see more of these events in the future due to climate change."