The latest assessment places 2025 in a longer historical context rather than focusing on a single year. According to the Met Office, the evidence shows sustained warming across annual, seasonal, monthly and daily timescales, with recent years consistently ranking among the warmest ever observed.
The report also highlights changes affecting rivers, coastlines and ecosystems, while researchers say many of the weather conditions experienced during recent heatwaves are no longer exceptional but are increasingly part of the UK’s climate.
Record Temperatures Highlight Long-Term Changes across the UK
According to the Met Office, 2025 was the warmest year in the UK record dating back to 1884, marking the sixth occasion this century that the national temperature record has been broken. The last four years all rank among the five warmest years ever recorded, while the decade from 2016 to 2025 was 1.33°C warmer than the 1961–1990 period.
Lead author Mike Kendon said the UK’s climate is “on the move” as warmer conditions spread northwards and into higher elevations. Areas including the Vale of York and Lancashire now experience annual temperatures similar to those recorded in Greater London between 1961 and 1990, while colder climatic conditions are retreating from mountain regions.
The report also identifies substantial changes in temperature extremes. In a broad area stretching from Kent to Lincolnshire, the average hottest day of the year has warmed by more than 4.5°C compared with the 1961–1990 average. Greater London has seen the number of days above 30°C and nights above 18°C more than quadruple over the same comparison period.
Mike Kendon said the evidence demonstrates that “the climate of the 20th century has now gone“, adding that temperature records across multiple timescales point to a period of historic change.
Rainfall, Sea Levels and Ecosystems Also Show Significant Shifts
The report records several notable environmental changes beyond temperature. According to the Met Office, 2025 brought the UK’s warmest spring and summer on record, while the surrounding seas experienced 297 marine heatwave days, the highest total since records began in 1982. It was also the sunniest year in the national sunshine series dating back to 1910.
Spring rainfall was exceptionally low across much of England and Wales, with most areas receiving less than half of the 1991–2020 average and some receiving less than one third. England recorded its driest spring for more than a century. At the same time, the report notes that winter half-years during the most recent decade have become wetter than in previous climate reference periods.
Sea level measurements also continued their long-term rise. According to the report, sea level around the UK has increased by about 20.1 centimetres since 1901, with roughly two-thirds of that rise occurring during the past three decades.
The report also documents ecological effects linked with the year’s weather conditions. The Woodland Trust said Nature’s Calendar recorded its highest seed yields since 2001 for several common tree and shrub species, including blackthorn and both pedunculate and sessile oak. Alex Marshall of the Woodland Trust said producing unusually large quantities of seed places considerable demands on trees, leaving them weaker and more exposed to prolonged heat and dry conditions.
