The year 2025 was among the three hottest years

According to the organization’s new analysis of eight data sets, the average global surface temperature was 1.44 degrees Celsius above the 1850-1900 average.

The organization’s Secretary-General, Celeste Saulo, said that the year 2025 began and ended with the cold La Niña phenomenon. “Yet it remains among the hottest years on record globally due to the buildup of greenhouse gases in our atmosphere.”.

She explained that rising land and ocean temperatures have contributed to fueling extreme weather phenomena – including heat waves, heavy rains, and severe tropical cyclones – which underscores the urgent need for early warning systems.

Saulo stressed that climate monitoring carried out by the World Meteorological Organization, which is based on the collection of collaborative and scientifically accurate global data, has become more important than ever before. “Because we need to ensure that information about the land is reliable, available and applicable to everyone.”.

The organization said that the actual global temperature in 2025 was estimated at 15.08 degrees Celsius. But she cautioned that there is a much larger margin of uncertainty regarding the actual temperature.

Ocean temperatures rise

The World Meteorological Organization also pointed to a separate study published in the journal Advances in Atmospheric Sciences that showed that ocean temperatures were also among the highest levels on record in 2025, reflecting the long-term buildup of heat within the climate system.
The study revealed that regionally, about 33% of the global ocean area was classified among the three warmest states recorded historically, while about 57% fell within the five warmest states, including the tropical and southern Atlantic Ocean, the Mediterranean Sea, the northern Indian Ocean, and the southern oceans, which confirms the widening scope of ocean warming across basins.

The study found that the global average annual sea surface temperature in 2025 was 0.49 degrees Celsius higher than the 1981-2010 baseline. But it was lower than it was in 2024, but 2025 still ranks as the third hottest year for the oceans.