From warmer winters and fewer frosts to increasingly intense summer heat, the UK’s climate is changing. But does this mean the seasons themselves are changing too?
The answer depends partly on how we define a season. Meteorologists use fixed three-month periods, with winter covering December, January and February, and summer running from June through August. These definitions remain unchanged, but the weather experienced within them is evolving.
Looking beyond individual years
The UK’s weather has always varied considerably from one year to the next. A warm, sunny summer can be followed by one dominated by cloud and rain, while a mild winter does not rule out periods of snow and ice.
This variability will continue in a changing climate. One season alone cannot demonstrate a long-term trend, so climate scientists use observations collected over many decades to identify changes in average conditions and weather extremes.
When these longer records are considered, the signs of change become much clearer.
Summers are becoming warmer
UK summers are getting warmer, although temperatures have not risen in a straight line and every summer will not necessarily be warmer than the last. Seven of the UK’s ten warmest summers on record have occurred since 2000, while all ten of the coolest occurred before 2000.
Changes in extreme heat are particularly noticeable. Heatwaves and prolonged hot spells are becoming more frequent and intense. In Greater London, the number of days exceeding 30°C in the decade 2016-2025 was four times that recorded during 1961–1990 when comparing these same periods. In parts of southeast England, the hottest day of the year has warmed by around 4.5°C.
READ MORE: Does a hot summer mean a cold winter?
The rainfall picture is less straightforward. Observations do not currently show a clear trend in total UK summer rainfall across June, July and August. Very wet summers, very dry summers and those falling somewhere in between all remain possible.
Climate projections nevertheless indicate a general movement towards hotter, drier summers. They also suggest that intense, short-lived rainfall, including thunderstorms and cloudbursts, could become stronger. This means a generally drier season could still produce disruptive downpours.
Research also suggests that weather patterns associated with summer could increasingly extend into September, effectively pushing summer-like conditions further into the meteorological autumn. And the heatwave of late May 2026 shows the potential for hot summer weather to extend earlier into spring, with the UK recording both 35°C and the UK’s first ‘tropical night’ (daily minimum temperature >=20°C) in a spring month; each smashing previous UK May records.
Winters are warmer and wetter
Winter is changing too. 2016-2025 was 0.6°C warmer than the 1991–2020 average and 1.4°C warmer than 1961–1990. For longer-term context, the Central England Temperature series shows that in this century so far, winter temperatures have increased by around 1.5°C compared to the 18th or 19th Centuries.
Frost is becoming less common, with both air and ground frosts reducing by around a quarter since the 1980s. The number of heating degree days, a measure of when buildings require heating, has also fallen.
READ MORE: Do changing seasons affect the jet stream?
Winters have become wetter as well. The winter half-year from October to March was 3% wetter during 2016–2025 than the 1991–2020 average, and 13% wetter than 1961–1990. The period from October 2023 to March 2024 was the wettest winter half-year in a series for England and Wales dating back to 1767.
Snowy weather has not disappeared, but substantial snow events and the average number of days with falling snow have declined. Cold spells can still happen, although they are occurring against a warmer climatic backdrop.
A shifting balance
The familiar characteristics of the UK’s seasons are not vanishing overnight. Grey summer days, cool spells, winter frosts and occasional significant snowfall will remain part of the country’s weather.
However, the balance is shifting. Summer heat is becoming more frequent and more intense, while winters are generally becoming milder, wetter and less snowy. Hot weather that we might typically expect to occur in summer has the potential to increasingly occur in late spring or early autumn, as our climate continues to change.
The calendar definitions of the seasons remain fixed, but the conditions we associate with them are changing. Understanding those changes will be increasingly important for water management, farming, ecosystems, infrastructure and public health as the UK prepares to adapt to our changing climate’.
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