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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the NewsPrism weather desk. Data from national met services via Open-Meteo.
A London heat wave is officially declared when temperatures reach or exceed 28°C for three consecutive days, though the capital often sees prolonged hot spells that push the mercury well above 30°C, particularly during July and August.
What counts as a heat wave in London?
The Met Office defines a heat wave as a period of at least three consecutive days when the daily maximum temperature meets or exceeds a specific threshold. For London, that threshold is 28°C, reflecting the urban heat island effect that makes the capital consistently warmer than surrounding areas. During a typical uk heatwave, temperatures in central London can be 2–5°C higher than in rural parts of the South East.
How does the London heat wave compare to the 2023 heatwave?
The heatwave uk 2023 saw London reach 32°C in early September, but it did not break the all-time records set in July 2022. The london heat wave 2023 was notable for its late-season timing, with the capital experiencing its hottest day of that year on 9 September. For current conditions, check the UK weather hub or the 10 day weather forecast UK.
Staying safe during extreme heat in London
When temperatures climb, the NHS advises keeping homes cool by closing curtains during the day and opening windows at night. Drink plenty of water, avoid alcohol, and never leave children or pets in parked cars. The RSPCA also warns that heat in london today can be dangerous for animals — ensure pets have shade and fresh water at all times.
When was London’s hottest day on record?
London’s highest recorded temperature was 40.2°C at Heathrow on 19 July 2022. This broke the previous record of 38.7°C set at Kew Gardens in July 2019.
Does London get heat waves every year?
Not every year, but they are becoming more frequent. Since 2000, London has experienced a heat wave in roughly two out of every three summers, with climate change increasing both the frequency and intensity of these events.
Is the Tube cooler during a heat wave?
No — the London Underground can become dangerously hot, with some deep-level lines reaching over 35°C. Carry water, wear light clothing, and consider using buses or overground trains on the hottest days.