Alarming changes to London’s weather were laid bare by a new report detailing how temperatures have soared.
The number of days over 30C and nights over 18C has more than quadrupled in London for the most recent decade, 2016-2025, compared to 1961-1990, according to the Met Office study.
Its annual “State of the UK Climate” report for 2025 highlighted how temperatures are spiralling in the capital at an increasingly worrying rate, with record high readings this year.
It also stressed that the “urban heat island” effect in London meant that the city was struggling to cool down and suffering more and more tropical nights, where temperatures do not dip below 20C.
The first two heatwaves of the year, in May and June, are estimated to have killed 1,000 people in the capital, its commuter belt and the wider South East, with hundreds of the deaths attributed to climate change.
The city has become so parched that the London Fire Brigade is urging people to create firebreaks around their gardens in the face of an “extreme” risk of wildfires.
Blazes erupted in Walthamstow, with flames ripping through around 30 gardens and damaging some properties, Stratford and Orpington over the weekend.
As London and other parts of the country are in the grip of a third heatwave for 2026, the Met Office stressed that the UK has already had as many 30C days this year as in infamously hot 1976.
There have now been 24 days in 2026 when 30C was exceeded in the capital or somewhere else in the UK; seven in May, eight in June and nine in July.
That equals the number of 30C-plus days in 1976, which lingers in the UK’s memory for its heatwave and drought conditions that forced people to use standpipes in the street, damaged crops and parched landscapes.
In its major report, the Met Office stressed that the UK’s climate of the 20th Century “has now gone”, as once-extreme conditions are increasingly seen as normal.
It explained how 2025 was the UK’s warmest year in records dating back to 1884, the sixth time the record has been broken in the 21st Century.
The last four years have all been among the top five warmest on record, and the latest 10 years from 2016 to 2025 were 1.33C warmer than the period from 1961 to 1990, the report shows.
The hottest day of the year is now 4.5C warmer than it was a few decades ago in parts of the South East, including London, and temperatures were expected to hit 35C at some point in the summer.
“In the South East we are seeing the emergence of new warmer climates,” said Mike Kendon, Met Office climate information scientist and lead author of the report.
“The number of days of over 30C has quadrupled in areas such as Greater London.”
He added: “In our northern upland areas we are losing the climatologically coldest habitats from the tops of our mountains.
“We are right now living in a time of historic and unprecedented change and in terms of temperature, on annual, seasonal, monthly and daily timescales, this evidence shows climate of the 20th Century has now gone.”
The report also showed most of England and Wales received less than half the average rainfall in spring, and some places had less than a third.
Since 1901, sea levels around the UK have risen by about 20.1cm but the rate of rise is accelerating.
The study was led by the Met Office, with contributions from the UK Centre for Ecology and Hydrology, National Oceanography Centre and the Woodland Trust’s Nature’s Calendar.
