The past 11 years have been the warmest in the modern era, with oceans continuing to absorb record levels of heat, the World Meteorological Organization (WMO) has said.
Confirming that 2025 was among the three warmest years on record, the UN weather agency said global temperatures remained extraordinarily high despite the presence of cooling climate patterns during the year.
After analysing eight international datasets, the WMO said global average surface temperatures in 2025 were 1.44 degrees Celsius above the 1850–1900 average, used as a benchmark for pre-industrial levels. Two datasets ranked 2025 as the second warmest year in the 176-year record, while the remaining six placed it as the third warmest.
The agency noted that 2025 was marginally cooler than the average of the previous three years, a trend partly attributed to the La Niña phenomenon. However, it stressed that any temporary cooling has not altered the long-term warming trajectory.
“The year 2025 started and ended with a cooling La Niña and yet it was still one of the warmest years on record globally because of the accumulation of heat-trapping greenhouse gases in our atmosphere,” Celeste Saulo, Secretary-General of the WMO, said.
La Niña refers to the periodic cooling of sea surface temperatures in the central and east-central equatorial Pacific Ocean. Such events typically occur every three to five years, though they can sometimes persist or recur over successive years.
The WMO also said elevated land and ocean temperatures helped fuel extreme weather events last year, including heatwaves, heavy rainfall and intense tropical cyclones, underscoring the importance of early warning systems.
Citing a separate study, the agency said ocean temperatures were also among the highest on record in 2025, reflecting the long-term build-up of heat within the climate system. About 33 percent of the global ocean area ranked among its historical top three warmest conditions between 1958 and 2025, while 57 percent fell within the top five, including the tropical and South Atlantic Ocean, the Mediterranean Sea, the North Indian Ocean and the Southern Ocean.
The WMO said it will release a comprehensive assessment of key climate indicators, including greenhouse gas concentrations, surface temperatures and ocean heat, in its ‘State of the Global Climate 2025’ report, due in March.
