Heavy thunderstorms and torrential rain marked the end of the UK heatwave, with the Met Office warning they could cause danger to life, sudden flooding and power cuts.
Thursday saw the highest temperature recorded in the UK since 2015, with the mercury in Faversham hitting 35.3C (95.5F).
While forecasts earlier in the week suggested Friday could see the record for the hottest July day broken, the hottest it got was 34.7C at Tibenham Airfield in Norfolk.
Yellow warnings are in place for most of England into the early hours of Saturday, and in north-east Scotland until 2pm.
Torrential downpours were forecast, with as much as 30mm of rainfall in one hour and 60mm in three hours, while large hail, frequent lightning and strong, gusty winds will be additional hazards.
Yellow warnings for rain have also been issued for Northern Ireland, with thunder possible.
The high was recorded in Tibenham, Norfolk, while the lowest temperature in Britain was in Tyndrum, Perthshire, where 8.6C was recorded.
"RNLI lifeboats and lifeguards have had four times as many rescues of inflatables so far this summer than they did last year."
York Racecourse tweeted to say the singer's show had been called off because of the "thunder and lightning storms".
"We were called following reports that a body had been found near to Clacton Pier shortly before 8am this morning, Saturday July 28.
"Police have provisionally identified him as 15-year-old Ben Quartermaine.
"The death is not being treated as suspicious but the cause of death is currently unknown and enquiries are ongoing. A file will be submitted to HM Coroner in due course."
"NATS is working closely with the airports and airlines to ensure safety and to continue providing the most efficient operation possible during this adverse weather period," a statement said.
"Dealing with bad weather is one of the most difficult things for air traffic controllers to manage.
"Its unpredictable nature means aircraft are not able to fly their usual routes, which results in unusual flight patterns.
"Thunderstorms are particularly disruptive as they effectively block large swathes of airspace because aircraft cannot fly through them.
"Passengers are advised to contact their airline for the latest information on individual flights."
A Stansted Airport spokesman said long queues shown in pictures posted on social media were caused by passengers who stayed overnight in the airport trying to re-book cancelled flights with airlines.
"There are no cancellations but there are delays because of the knock-on effect and some restrictions because of storm activity in Europe," he said.
"All the advice is, if you are due to travel today, check with your airline about your individual flight."
Gatwick Airport said on Twitter: "Adverse weather across Europe is affecting flights in and outbound from Gatwick Airport, this may result in delays and cancellations.
"Please contact your airline for specific flight information before you travel to the airport."
Similarly, Luton Airport tweeted: "Due to thunderstorm activity across Europe this morning, air traffic control restrictions are in place and some flights may be subject to delay or cancellation."
A Heathrow Airport spokeswoman said: "We seem to be experiencing some minor delays."
Passengers travelling to France on cross-Channel rail operator Eurotunnel have been warned they could face waits of up five hours at its Folkestone terminal.
Families heading for summer getaways on the Continent by ferry were told to expect long queues on the roads into the Port of Dover with a minimum two-hour wait to get through border checks.
P&O ferries advised its customers to take plenty of drinks, snacks and entertainment for their wait.
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While some will have welcomed the rain and the cooler temperatures, those keen to catch a glimpse of the blood moon, the longest lunar eclipse of the 21st century, will have been disappointed.
The cloud cover meant the rare celestial event was not visible to many from Hampshire and Wiltshire in the south and south west, to Hull in east Yorkshire, Liverpool in the north west and Dublin in Ireland.
Meanwhile, police forces have been called following concerns for people’s welfare at rivers and a lake.
Thames Valley Police said a man’s body was recovered from the Jubilee River in Slough, adding that his death is not being treated as suspicious.
Warwickshire Police said emergency services personnel searching for a 17-year-old boy who disappeared after getting into difficulty in a quarry lake in Bishops Itchington, near Leamington Spa, have recovered a body.
Essex Police said the body of a teenager who went missing near Clacton Pier on Thursday evening has been found.
Bedfordshire are also looking for a man who got into difficulties in the river Great Ouse on Friday afternoon.
Elsewhere, cross-Channel rail operator Eurotunnel cancelled thousands of tickets after “extreme temperatures” caused major disruption to services.
On UK trains, passengers were urged to avoid travelling on London North Eastern Railway (LNER) on Friday after lightning damaged the signalling system.
Train firm Northern advised passengers not to travel in the Yorkshire area due to the same issue.
On the roads, motorists were warned of lightning, flash flooding and large hailstones.
A mix of toxic air, extreme highs, emissions from the continent and a lack of cloud cover caused a “high” air pollution alert to be issued for London.
Elsewhere, authorities said the heatwave was causing “winter conditions” in parts of the NHS, while many nurses were said to be dizzy and exhausted.
Additional reporting by agencies
