A “surprising” record: January 2025 was the hottest month ever measured in the world

January 2025 was the hottest month ever measured in the world, the European Copernicus Observatory announced on February 6, 2025.

January broke the record set last year, despite the end of the El Niño phenomenon that accentuated global warming in 2023-2024.

“January 2025 is another surprising month, continuing the record temperatures seen over the past two years, despite the development of La Niña conditions in the tropical Pacific and their temporary cooling effect on global temperatures” the opposite of El Niño, said Samantha Burgess, Deputy Director of Copernicus' Climate Change Service (C3S).

What does the Paris Agreement say?

With an average temperature of 13.23°C according to Copernicus, “January 2025 is 1.75°C above pre-industrial levels”, before humans changed the climate with the massive use of coal, oil and fossil gas.

January 2025 is thus “the eighteenth of the last nineteen months for which the average air temperature at the surface of the globe has exceeded the pre-industrial level by more than 1.5°C”, notes the European observatory.

This is more than the +1.5°C mark, corresponding to the most ambitious limit of the 2015 Paris Agreement, which aims to contain global warming well below 2°C and to pursue efforts to limit it to 1.5°C.

However, this agreement refers to long-term trends: such an average of warming will have to be observed over at least 20 years to consider the limit crossed.

The 1.5°C mark reached between 2030 and 2035

Taking this criterion, the climate is currently warming by around 1.3°C. The IPCC estimates that the 1.5°C mark will probably be reached between 2030 and 2035. And this, regardless of the evolution of humanity's greenhouse gas emissions, close to the peak but not yet in decline.

Global temperatures are highly dependent on those at the surface of the seas, a primary regulator of the climate that covers more than 70% of the globe. But water temperatures are still at levels not seen before April 2023.

For the surface of the oceans, January 2025 ranks as the second warmest month after the absolute record of January 2024.

But Copernicus notes signs “of a slowdown or a halt in the evolution towards La Niña conditions”, in other words a lesser cooling effect on global temperatures in 2025.