New data from the Copernicus Climate Change Service (C3S) has revealed that June 2025 was the third-warmest on record, globally, with the average global surface air temperature reaching 16.46°C.
This is 0.47°C above the 1991–2020 average and 1.3°C above pre-industrial levels, the data showed, although temperatures were slightly down on both June 2024 and June 2023.
Over the 12-month period running from July 2024 to June 2025, the average global temperature has stood at 1.55°C above pre-industrial levels, while just three out of the past 24 months have fallen below the 1.5°C threshold.
‘Exceptional heatwave’
June 2025 was the fifth-warmest June on record across the European continent, however in Western Europe, it was the warmest of all time – with average temperatures of 20.49°C, or 2.81°C above the 1991–2020 norm.
The continent saw two major heatwaves occur in June, which affected large parts of western and southern Europe, with parts of Portugal reaching extreme heat stress – ‘feels-like’ temperatures reached as high as 48°C.
“June 2025 saw an exceptional heatwave impact large parts of western Europe, with much of the region experiencing very strong heat stress,” commented Samantha Burgess, strategic lead for climate at ECMWF.
“This heatwave was made more intense by record sea surface temperatures in the western Mediterranean. In a warming world, heatwaves are likely to become more frequent, more intense and impact more people across Europe.”
Outside of Europe, temperatures were mostly above average over the United States, northern Canada, central Asia, eastern Asia, and west Antarctica, while they were below average over southern South America, with record cold conditions recorded in Argentina and Chile.
Sea surface temperatures
Elsewhere, global sea surface temperatures displayed concerning trends, with the average sea surface temperature between 60°S and 60°N coming in at 20.72°C in June, the third-highest on record for the month.
The western Mediterranean in particular experienced an ‘exceptional marine heatwave’, the data showed.
Arctic sea ice extent was 6% below average, the second lowest June extent in the 47-year satellite record. Read more here.
