The World Meteorological Organization (WMO) has confirmed that 2025 was one of the three warmest years on record, extending a run in which the past 11 years have been the 11 warmest since modern measurements began. Ocean warming also continued unabated, reinforcing long-term climate trends.
According to WMO’s consolidated analysis of eight global temperature datasets, the global average surface temperature in 2025 was 1.44°C above the 1850-1900 average, with a margin of uncertainty of ±0.13°C. Two datasets ranked 2025 as the second warmest year in the 176-year record, while the remaining six ranked it third warmest.
The years 2023-2025 were the three warmest years in all eight datasets, with a consolidated three-year average temperature of 1.48°C above pre-industrial levels. The period 2015-2025 represents the warmest 11-year span across all datasets.
“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,” said WMO secretary-general Celeste Saulo. “High land and ocean temperatures helped fuel extreme weather – heatwaves, heavy rainfall and intense tropical cyclones – underlining the vital need for early warning systems.”
WMO said its climate monitoring work is increasingly important to ensure Earth system information is authoritative and accessible. “WMO’s state of the climate monitoring, based on collaborative and scientifically rigorous global data collection, is more important than ever,” Saulo added.
The announcement coincided with temperature updates from the major dataset providers, including Copernicus ERA5, NASA GISTEMP, NOAAGlobalTemp, the UK Met Office HadCRUT, Japan Meteorological Agency JRA-3Q and Berkeley Earth. For the first time, WMO also included the DCENT and China Merged Surface Temperature (CMST) datasets.
Six datasets are based on surface observations from weather stations, ships and buoys, while two – ERA5 and JRA-3Q – are reanalyses combining observations and models. While methodologies differ slightly, WMO consolidates the data to provide a single authoritative assessment.
The actual global temperature in 2025 was estimated at 15.08°C, although WMO noted a larger uncertainty margin of around 0.5°C for absolute temperature values.
A separate study published in Advances in Atmospheric Sciences reported that ocean heat content in 2025 was among the highest on record, with the upper 2,000 meters of the ocean gaining an estimated 23±8 zettajoules of heat from 2024 to 2025. The study also found that global sea surface temperatures in 2025 ranked as the third warmest on record, despite a slight cooling associated with La Niña conditions.
WMO will publish its State of the Global Climate 2025 report in March 2026.
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