The EU’s Copernicus Climate Change Service (C3S) is reporting that last month saw the third-warmest June globally with heatwaves in Europe amid temperature extremes across both hemispheres.

Implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission with funding from the EU, routinely publishes monthly climate bulletins reporting on the changes observed in global surface air and sea temperatures, sea ice cover and hydrological variables.

Most of the reported findings are based on the ERA5 reanalysis dataset, using billions of measurements from satellites, ships, aircraft and weather stations around the world.

Key findings for June 2025 include the following surface air temperature and sea surface temperature highlights:

Global Temperatures

• June 2025 was the third-warmest June globally, with an average ERA5 surface air temperature of 16.46°C, 0.47°C above the 1991-2020 average for June.
• June 2025 was 0.20°C cooler than the record June of 2024, and 0.06°C cooler than June 2023, which was the second warmest.
• June 2025 was 1.30°C above the estimated 1850-1900 average used to define the pre-industrial level. It was only the third month in the last 24 with a global temperature less than 1.5°C above the pre-industrial level.*
• The 12-month period of July 2024 – June 2025 was 0.67°C above the 1991-2020 average, and 1.55°C above the pre-industrial level.

Heatwaves likely to become more frequent, more intense and impact more people across Europe

According to Samantha Burgess, Strategic Lead for Climate at ECMWF:

"June 2025 saw an exceptional heatwave impact large parts of western Europe, with much of the region experiencing very strong heat stress. 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.”

The average temperature over European land for June 2025 was 18.46°C, 1.10°C above the 1991-2020 average for June, making the month the fifth-warmest June in the record.

Most of western and central Europe experienced warmer-than-average air temperatures in June 2025. Western Europe as a whole saw its warmest June on record, with an average temperature of 20.49°C, 2.81°C above the 1991–2020 average. It narrowly surpassed (by only 0.06°C) the previous June record set in 2003 (20.43°C).

Two major heatwaves in mid- and late June 2025 affected large parts of western and southern Europe. Much of the region saw feels-like temperatures exceeding 38°C, corresponding to ‘very strong heat stress’. Parts of Portugal saw feels-like temperatures reach around 48°C or ‘extreme heat stress’. An additional analysis of these heatwaves can be found here.

Outside Europe, temperatures were most above average over the United States, northern Canada, central Asia, eastern Asia, and west Antarctica.

Temperatures were most below average over southern South America, with record cold conditions recorded in Argentina and Chile. India and east Antarctica also had below-average temperatures.

Sea surface temperature

The average sea surface temperature (SST) for June 2025 over 60°S–60°N was 20.72°C, the third-highest value on record for the month, 0.13°C below the June 2024 record.

An exceptional marine heatwave developed in the western Mediterranean in June, leading to the highest daily SST ever recorded for the region as a whole in June (27.0°C), corresponding to the highest daily SST anomaly for any month (3.7°C above average).

June 2025 – Hydrological highlights

In June 2025, it was drier than average in western and southern Europe, as well as much of the UK and regions of southern Scandinavia, and parts of western Russia.

Conversely, it was wetter than average in Iceland, Ireland, the northern UK, Denmark, much of Fennoscandia, the Baltic states, Belarus, and parts of Ukraine and Russia.

Conditions were predominantly drier than average in large parts of northern USA and Canada, eastern Africa, the Arabian Peninsula, central Asia, easternmost China and Japan, much of Australia, southern Africa, as well as large regions of southern South America.

It was wetter than average in the southern USA and northern Mexico, northern and south-western Asia, parts of China, northern Australia, and southern Brazil.

Relative humidity averaged over European land areas reached a new record low for June, at 2.7% below average, slightly below the previous record of -2.3% set in June 2022.

Sea ice in June

Arctic sea ice extent was 6% below average, the second lowest monthly extent for June in the 47-year satellite record. During the latter part of the month, the daily extent was consistently the lowest for the time of year.

Regionally, below-average sea ice concentrations were most pronounced along the northern coast of Eurasia (Barents, Kara, and Laptev Seas).

Antarctic sea ice extent was 9% below average, ranking as 3rd lowest value on record for the month.

Antarctic sea ice concentrations were dominated by below-average concentrations in the Bellinghausen Sea and eastern South Atlantic and average or above-average concentrations in the other ocean sectors.