The UK experienced the joint hottest day of the year so far with temperatures reaching 32.2C on Sunday.
The warmest part of the country was Coningsby in Lincolnshire, matching this year’s record set on 10 June in Chertsey in Surrey.
Coningsby is also where the UK’s hottest ever temperature of 40.3C was recorded on 19 July last year.
However, thunderstorms and heavy showers were expected to hit northern England, Scotland and parts of Northern Ireland on Sunday evening, with up to 30mm of rain expected in some parts of the north-east.
A yellow weather warning for thunderstorms was in place across eastern Scotland and north-east England from 1pm until 9pm on Sunday.
Met Office meteorologist Amy Bokota said: “Stay hydrated and make sure you are wearing sun protection as we have high UV levels.
“Make sure you are not putting any disposable barbecues on any grassland area.”
The weather is expected to cool next week, with fresher air expected, particularly in the south-east.
Temperatures in London were not expected to surpass 24C on Monday, representing “quite a significant drop”.
Bokota said it was “likely to feel a lot more comfortable than it has done for the last couple of weeks”.
The Met Office warned people to be sensible and enjoy the heat responsibly.
A teenage girl died in Lincolnshire after being pulled from the sea on Saturday evening.
The 15-year-old girl and a teenage boy were airlifted to hospital from Cleethorpes beach.
Humberside police said: “We can confirm that a girl, aged 15, has sadly passed away following a multi-agency search to locate two missing children off the coast of Cleethorpes, north-east Lincolnshire.”
The boy was later discharged from hospital after receiving medical care.
Meanwhile, the London fire brigade said 10 fire engines and about 70 firefighters were dispatched to tackle a grass blaze on Rammey Marsh in Enfield in the north of the city. About two hectares of grassland were alight on Sunday afternoon.
PA Media contributed to this report.
