Fact Check: Was June Hottest Month?


Tweets have been circulating on social media declaring that June 2019 was the hottest month ever recorded. For example …

So was it?

Quick Answer: Nope.

Slightly longer answer is this correction from Climatologist Michael E Mann …

But how do we know?

The alpha source for all of the latest “Hottest” claims comes from The Copernicus Climate Change Service (C3S). C3S is one of six thematic information services provided by the Copernicus Earth Observation Programme of the European Union, so yes, they are a reliable source.

What data did they provide?

Basically this …

Data released today show that the European-average temperature for June 2019 was higher than for any other June on record. 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. 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.

OK, that appears to be clear … “higher than for any other June on record” … ah but, pause and read that again. Here let me do that for you … “the European-average temperature for June 2019 was higher than for any other June on record“.


So they are reporting averages for just the EU and not the entire globe.

Well not quite.

They also report this …

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.

So the facts are that June 2019 was indeed the hottest June ever recorded on planet earth within their dataset.

Average June temperatures (°C) for Europe (top) and globally (bottom) from 1979 to 2019, shown as differences from long-term average values for 1981 to 2010. June 2019 is highlighted. Data source: ERA5 (credit: ECMWF, Copernicus Climate Change Service).

What if we look further back, is it still the Hottest June?

Official records go back to about 1880, so if we take the above and stretch the timeline all the way back (and include all other warm Junes in that timescale), what happens?

Basically this …

Average June temperatures (°C) for Europe (top) and globally (bottom) from 1880 to 2019, shown as differences from long-term average values for 1850 to 1900. June 2019 is highlighted. Data sources: ERA5 (ECMWF, Copernicus Climate Change Service) and HadCRUT4 (Met Office Hadley Centre and Climatic Research Unit, University of East Anglia).

As you can see, spikes in European-average June temperature of more than 1°C above normal have occurred several times during the last 150 years; For example, in 1901 and 1917, as well as 1999.

June 2019 was exceptional. This latest 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, commented as follows…

“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.”

He is of course being polite and sticking to the facts. 

To translate from his EU speak – “If we don’t address Climate change the we are F***ed”

Sanity Check: This data comes from just one dataset. It will be interesting to see what the other independent datasets report as they become available.

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