Londoners recently faced a jarring weather one-two punch. First was a muggy overnight heat spell that was unusual for September, followed by a forecast for thunderstorms moving across the capital.
Here's what to know
Forecasters called for thunderstorms between 9 a.m. and 10 a.m. in London, even though the city was still on track to warm up again in the afternoon after temperatures remained unusually high through the night, according to The Standard.
Before any storms moved in, London had already recorded a rare September "tropical night." The Met Office uses that term when temperatures stay above 68 degrees Fahrenheit (20°C) overnight, and in the capital the reading reportedly hit 71.2 (21.8°C) at 2 a.m.
Even with the unsettled start, temperatures were still expected to reach 77 or 78.8 (25 or 26°C) in the afternoon, after London had already climbed to 82.4 (28°C).
BBC Weather meteorologist Chris Fawkes said the pattern pointed to a stormy morning, warning of "heavy bursts" of rain.
"We've got an unsettled start to the day," Fawkes said, per The Standard. "Low pressure to the north-west of the UK is driving across the country."
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"For many of us it's going to be a wet start to the morning," Fawkes said.
More background
On X, meteorological account London & Southeast (@TheSnowDreamer) called the overnight warmth "historically late" and "unknown for time of year," saying inner London, including St James's Park, appeared to have stayed above the 68-degree (20°C) mark.
Historically late tropical night unknown for time of year. Still needs to be confirmed Heathrow fell just short 19.9C but seems inner London, St James's Park stayed above 20C. https://t.co/gC0eutl1zv
— London & Southeast 🔆 (@TheSnowDreamer) September 30, 2026
London saw similarly dramatic conditions in June, including an overnight lightning display with thousands of strikes, as The Standard reported at the time.
Another round of thunderstorms in June was linked to a fire at a property in Streatham.
What's being done?
This recent bout of extreme weather showed that London is far from out of the woods after it dealt with extreme heat and major thunderstorm earlier in the year.
As the world gets hotter, what were once rare weather events or conditions are becoming increasingly common. Long-term steps like reducing our contributions to the warming of the planet is one way to address the overall problem.
Building up resiliency in the short-term against flash flooding is another step that can be taken.
For extreme heat, making sure that more vulnerable people like the elderly and those without cooling are OK will be important as hot days crop up at unusual times in the calendar.
Where can I learn more?
London's heat and stormy forecast fits into a broader context of extreme weather in the continent.
• Across Europe, tropical nights may pose threats even as temperatures approach 104 F.
• In the U.K., record-breaking heat had doctors warning of mounting health dangers.
• Across the U.K., flooding and 80 mph winds brought unnerving conditions during Storm Ashley.
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