Over the last 19 months, 18 have seen global average surface temperatures at least 1.5 degrees Celsius above pre-industrial levels, continuing a concerning trend of record-breaking temperatures.

"January 2025 is another surprising month, continuing the record temperatures observed throughout the last two years, despite the development of La Niña conditions in the tropical Pacific and their temporary cooling effect on global temperatures," said Samantha Burgess of the Copernicus Climate Change Service.

This means that January 2025 stands out as anomalous even by the standards of the last two years,” Hausfather explains. Writing for Discover Magazine, Tom Yulsman points out that scientists expected this January to be cooler than preceding Januaries because of the ocean current cycles like El Niño and La Niña.