From record ocean heat to the UK’s warmest year on record, 2025 provided further evidence of a global climate system continuing to warm.
However, the year did not unfold uniformly. Different regions experienced contrasting combinations of heat, rainfall, drought and storms, while the UK’s most notable feature was the persistence of warmth across several seasons.
According to a paper published by the Met Office Hadley Centre, 2025 ranked as the third warmest year globally, but in the UK it moved to the top of the record. That contrast tells only part of the story: record ocean heat, declining sea ice, regional droughts and episodes of extreme rainfall all contributed to a year in which the warming climate was expressed in markedly different ways around the world.
Key global indicators of climate change. (a) Global mean temperature anomalies (1850–2025), °C relative to 1981–2010. (b) Monthly carbon dioxide concentration in the atmosphere (1960–2025), ppm. (c) Annual ocean heat content anomalies (1950–2025), 1022J relative to 1981–2010. Four EN4 ensemble members are plotted here: L09, G10, C13 and C14. These members are each subject to different bias corrections, as described in the introduction (Section 1) of the EN4 user guide3. (d) Monthly global mean sea level anomalies (1993–2025), mm relative to 1993–2010. (e) Cumulative annual glacier mass balance (1950–2025), metres water equivalent relative to 1970. (f) Arctic sea ice extent anomalies for March and September (1979–2025), million km2 relative to 1981–2010. Data sourced from https://climate.metoffice.cloud/ and references therein.
A globally warm year
Globally, 2025 was the third warmest year in records dating back to 1850. The annual average global surface temperature was 1.43 ± 0.13°C above the 1850 to 1900 average, behind only 2024 and 2023. All months from January to November ranked among the three warmest examples of their respective calendar month in the HadCRUT5 global temperature record.
Global temperatures were slightly lower than in 2024, partly reflecting the transition away from the 2023 to 2024 El Niño. During 2025, conditions in the tropical Pacific were mainly neutral or weakly La Niña, which are generally associated with lower global temperatures than El Niño years. Even so, 2025 was the warmest year on record where El Niño conditions did not occur during at least part of the year.
Against the background of a warming world, the UK experienced its warmest year on record. Its average daily mean temperature reached 10.10°C, while average daily maximum temperature reached 14.01°C, both the highest in the HadUK-Grid series. The Central England Temperature series, which stretches back to 1659, also recorded its warmest year, with an annual mean of 11.23°C.
Caroline Sandford, Senior Scientist at the Met Office, said: "What really stands out about 2025 is that, even without the influence of El Niño, global temperatures were almost as high as the record-breaking years of 2023 and 2024. We can see how the long-term warming trend is continuing to raise the baseline for what we expect in any given year.
"For the UK, last year that manifested not in one extraordinary heatwave, but in the persistence of above-average temperatures across multiple seasons. When unusual warmth is sustained over longer periods like this, it has a much greater influence on annual records and provides a clear illustration of how our climate is continuing to change."
Persistent warmth made the difference
The UK’s new record was not driven by a single exceptional hot spell. Although the highest temperature of the year was 35.8°C at Faversham in Kent, frequent and sustained periods of warmth pushed annual averages to record levels. Almost every month was at least 1°C warmer than the 1981 to 2010 average, with March to August all ranking among the ten warmest examples of those months.
Both spring and summer were the warmest on record for the UK. Spring maximum temperatures were 2.86°C above the 1981 to 2010 average, while summer’s average daily mean temperature exceeded the previous record, set in 2018, by 0.3°C.
LEARN MORE: UK climate data
Globally, some of the most pronounced warmth occurred at high northern latitudes. Western Russia and parts of the Arctic Circle were more than 3°C warmer than average during winter, while the Arctic experienced its warmest 12-month period on record from October 2024 to September 2025.
Europe also had its third warmest year, with summer heat particularly notable across France and Spain. Farther north, sub-Arctic parts of Finland, Norway and Sweden experienced an extended heatwave, with temperatures above 30°C recorded somewhere in Finland every day from 12 July to 1 August.
A year of rainfall contrasts
The UK’s record warmth was accompanied by marked changes in rainfall through the seasons. Spring received only 54% of its average rainfall, making it the sixth driest spring on record for the UK as a whole, while England experienced its driest spring for more than a century. It was also the UK’s sunniest spring on record.
Summer rainfall recovered to 90% of average nationally, but dry conditions persisted in southern and eastern England. A wet autumn followed, although some areas remained in drought because of the earlier rainfall deficit.
READ MORE: State of the UK Climate
Comparable contrasts occurred globally. Parts of northwestern Africa, southwestern Asia and the Middle East received less than 60% of normal annual rainfall. Meanwhile, an early monsoon brought flooding to several Asian countries, and parts of India recorded around twice their average spring rainfall.
Signals across the climate system
The temperature record is only one measure of the changing climate. Ocean heat content reached another record in 2025, continuing an unbroken sequence of annual records since 2017. The oceans absorb around 91% of the excess heat associated with the Earth’s energy imbalance.
Arctic sea ice also reached a record-low annual maximum in March, while Antarctic sea ice fell to its joint second-lowest minimum. Atmospheric greenhouse gas concentrations continued to rise, providing the underlying driver of long-term warming across the climate system.
Caroline Sandford, Senior Scientist at the Met Office, said: "When we look at the climate system as a whole, the message extends far beyond air temperatures alone. Record ocean heat, shrinking sea ice, rising sea levels and melting glaciers all point in the same direction. The oceans, in particular, are absorbing the vast majority of the excess heat being trapped in the climate system as a result of rising greenhouse gas concentrations.
"The fact that these indicators are continuing to set records alongside exceptionally high global and UK temperatures provides strong evidence of the scale and persistence of long-term climate change."
READ MORE: The Met Office Climate Dashboard
The comparison is clear: global temperatures remained exceptionally high, while the UK experienced its warmest year on record through persistent warmth rather than one isolated event. The details varied by region and season, but the broader indicators continue to show a climate responding to increasing greenhouse gas concentrations.
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