The year 2025 was among the top three warmest years on record, according to the latest update from the World Meteorological Organization (WMO).

Depending on the data set being used, the year was either the second or third warmest year on record.

The UN agency for monitoring the atmosphere also confirmed that the past 11 years have been the 11 warmest on record, and ocean heating continues unabated.

The global average surface temperature in 2025 was 1.44°C (with a margin of uncertainty of ± 0.13°C) above the 1850-1900 average that is used as a pre-industrial era baseline, WMO reported.

“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. High land and ocean temperatures helped fuel extreme weather – heatwaves, heavy rainfall and intense tropical cyclones, underlining the vital need for early warning systems,” said WMO Secretary-General Celeste Saulo.

This update from the WMO comes less than two months after global leaders met in Brazil’s Belém for the annual UN climate conference, COP30. It confirms that the climate action so far is proving to be woefully inadequate as the streak of extraordinary global temperatures continues unabated.

A robust data set

What makes this data robust is that it is a consolidated analysis of eight different global datasets. Two of these datasets ranked 2025 as the second warmest year in the 176-year record, and the other six ranked it as the third warmest year.

The past three years, 2023-2025, are the three warmest years in all eight datasets. The consolidated three-year average 2023-2025 temperature is 1.48 °C (with a margin of uncertainty of ± 0.13 °C) above the pre-industrial era. The past 11 years, 2015-2025, are the 11 warmest years in all eight datasets.

“WMO’s state of the climate monitoring, based on collaborative and scientifically rigorous global data collection, is more important than ever before because we need to ensure that Earth information is authoritative, accessible and actionable for all,” said Saulo.

The update was timed to coincide with the release of global temperature announcements from the respective dataset providers.

One of the eight datasets is one from the National Oceanic and Atmospheric Administration (NOAA), the US agency that has had its funding cut by the Trump administration. Other data sets are from the European Union, Japan, China and the UK.

Six of the eight datasets are based on measurements made at the weather stations, and by ships and buoys using statistical methods to fill gaps in the data. Two of the datasets combine past observations, including satellite data, with models to generate a consistent time series of multiple climate variables, including temperature.

The actual global temperature in 2025 was estimated to be 15.08°C, but there is a much larger margin of uncertainty on the actual temperature at around 0.5°C than on the temperature anomaly for 2025, WMO said.

Oceans continue to heat

Roughly 90% of excess heat in the atmosphere is absorbed by the world’s oceans, warming them in the process. This makes ocean heat a critical indicator of climate change.

A separate study published in Advances in Atmospheric Sciences reports that ocean temperatures were also among the highest on record in 2025, reflecting the long-term accumulation of heat within the climate system. And while warming temperatures affect life on Earth, the warming oceans pose a threat to the coral reefs and life in the water.

From 2024-2025, the global upper 2000m ocean heat content (OHC) increased by ∼23 ± 8 Zettajoules relative to 2024, according to the study led by Lijing Cheng with the Institute of Atmospheric Physics at the Chinese Academy of Sciences. That is around 200 times the world’s total electricity generation in 2024.

Regionally, about 33% of the global ocean area ranked among its historical (1958–2025) top three warmest conditions. Another 57% fell within the top five, including the tropical and South Atlantic Ocean, Mediterranean Sea, North Indian Ocean, and Southern Oceans, underscoring the broad ocean warming across basins.

While the global annual mean sea surface temperature (SST) in 2025 was 0.12 ± 0.03°C lower than in 2024, it was 0.49°C above the 1981–2010 baseline, showing long-term warming trends.

State of the Global Climate 2025 report

While the current update was meant to give an indication of the global temperature trend, WMO’s State of the Global Climate 2025 report to be issued in March will go further.

WMO will provide a detailed breakdown of key climate change indicators, including greenhouse gases, surface temperatures, ocean heat, sea level rise, glacier retreat and sea ice extent.

The datasets being relied by the WMO provide a near-complete global picture of near-surface measurements using statistical methods to fill gaps in data-sparse areas such as the polar regions.

Image Credits: WMO, WMO, WMO, Markus Spiske/ Unsplash.