Thunderstorms and heavy downpours are due to hit the UK in a “big change” in conditions after the end of the heatwave, the Met Office has said.
It comes after record-breaking temperatures baked the country earlier this week, with 35.1C measured in Kew Gardens, west London, and 32.9C recorded at Cardiff’s Bute Park, on Tuesday.
On Sunday, Bushy Park in Richmond upon Thames saw the highest temperature of the day at 24.7C, the Met Office said.
Rebecca Mitchell, senior operational meteorologist at the weather service, said: “Going into next week, there is a big change on the way.
“We’ve got spells of rain, possible thunderstorms, and some strengthening winds through much of the week.
“The other part of the story is the temperatures will be much lower compared to the week just gone.
“They’ll be around average for the time of year, which typically is around 17 to 19 degrees in the north and around 18 to 21 degrees in the south, so about 14 degrees lower in some places compared to the previous week.”
On Monday, heavy rain is expected to cross the whole country, bringing large rainfall particularly in parts of Wales, Ms Mitchell said.
“We’re not expecting too many impacts from this because it has been so dry recently for many places, and actually for some areas the rain will be welcome, I think, for gardeners, farmers, anyone hoping for some rain,” she said.
“And then, following that, into Tuesday, we’ve got some heavy showers and potential thunderstorms.
“The main areas likely to see some thunderstorms would be central and southern areas, so Northern Ireland, northern England, southern England, and Wales.”
For the rest of the week, much of the county will see “unsettled weather” along with some sunny spells and highs of low-20Cs, she said.
The cooler conditions come after at least 14 people died during the heatwave after getting into difficulties in bodies of water, prompting emergency services to issue safety warnings.
On Sunday evening, South Yorkshire Police said officers would remain overnight at the river Don in Mexborough after the force had received reports that an 11-year-old boy had entered the water on Saturday evening but had not been seen getting out.
Officers were called to the scene at Ferry Boat Lane at 7.59pm on Saturday and emergency crews from the National Police Air Service, Yorkshire Ambulance Service and the South Yorkshire Fire and Rescue Services also responded, police said.
The boy has not been found despite a multi-agency search of the the river, the riverbank, and nearby open land, with an underwater search team and Mountain Rescue also involved.
The boy’s family had been informed and were being supported by specially trained officers.
Police Constable Simon Bennett, police search adviser, said in a statement: “As we have now lost daylight, the search has become more challenging and we will have to await first light to resume extensive search activities, but we aren’t giving up – police officers will remain at the river Don overnight and we are already putting plans in place for further searches of the river Don and nearby land tomorrow.
“We have had so many offers of help but, for everyone’s safety, must ask people to refrain from conducting their own searches of land or water – we have enough resources to continue the search and have access to a national network of specialists should we need them in the coming days.”
Thousands of people in Kent were without drinking water or experienced disruptions to their supply over the weekend as South East Water continued to grapple with issues following the hot weather.
On Sunday evening, the company said drinking water supplies had been restored for “most customers” across the county, including those in Whitstable and Herne Bay.
Some 4,058 customers may still be experiencing low pressure or intermittent supply in areas including Whistable, Coxheath and Loose, South East Water said.
The company apologised for the disruption and said it was working to resolve the issues.
