An amber heat health alert has been issued for London and other parts of the UK from Friday, as temperatures could reach highs of 31C.
The UK Health Security Agency (UKHSA) issued the alert covering the East Midlands, South East, South West, East of England and London.
Heatwaves will return to the capital after a slight drop in temperature in the past few days.
Friday will see highs of 29C with sunny and cloudy conditions, while temperatures will reach as high as 29C on Saturday, according to the Met Office.
Sunday is set for clear skies and dazzling sunshine as the temperature hits 31C in the afternoon and evening.
London is forecast to be even hotter on Monday, when the mercury could reach 34C.
This will mean a blistering start to the Wimbledon Tennis Championships, which begin on Monday, with the hottest first day in its 147-year history.
Saturday was the hottest day of the year so far with temperatures rising to 33.2C (91.8F) in the village of Charlwood near London Gatwick Airport.
In London, a heatwave is triggered when a location records at least three consecutive days where the daily maximum temperature meets or exceeds 28C.
The UKSHA alerts begin at 12pm on Friday and end at 6pm on Tuesday July 1.
The agency has warned that significant impacts are likely across health and social care services, including an increase in demand, during the alert period.
An amber alert was previously issued for all regions in England on June 19, the first time it had been used since September 2023.
On the same day the UK recorded its warmest day of the year so far, with temperatures reaching 32.2C in Kew, west London, before heatwaves were declared across England and Wales.
Thunderstorms are possible with warm, humid air set to linger in the south and east on Thursday, with maximum temperatures of 27C in eastern England, the Met Office said.
A yellow alert has also been issued for Yorkshire and Humber and the West Midlands.
