It is the third day of a red warning for extreme heat in the South.
On Friday the warning is in place for parts of Hampshire, Berkshire and Oxfordshire with an amber alert for a wider area until midnight.
The search for a 15-year-old boy missing after going swimming in a lake is continuing at Testwood Lakes.
A new record June temperature of 36.1C (87F) that was set in Gosport, Hampshire on Wednesday was eclipsed by Yeovilton, Somerset on Thursday.
The NHS in Hampshire alongside hospitals in Southampton and Portsmouth and South Central Ambulance Service declare critical incidents.
Several rail operators have extended their reduced service due to the extreme heat into Friday.
About 200 schools across the region have announced closures or reduced hours due to the heat.
There were thunderstorms with dramatic lightning in Dorset on Thursday night.
Follow this advice to keep yourself and your home as cool as possible.
The Met Office has recorded a provisional temperature of 36.4C at Yeovilton, Somerset, making it the hottest June day on record.
This beats yesterday's hottest June temperature record of 36.1C in Gosport, Hampshire, which broke the longstanding record from 1976.
Image source, Getty ImagesSouthern Water has said it does not have any "immediate plans" to introduce a hosepipe ban.
It added it was "monitoring our water resources carefully, especially the chalk streams in Hampshire, the River Test and River Itchen, which supply most of the water to customers in that area".
It encouraged people to keep using water responsibly and said while demand for water was forecast to hit 684m litres, people actually used 661m litres on Wednesday.
According to its past figures the average demand for water last June was about 589m litres daily, with the demand expected to hit 650 million litres in "normal" hot weather.
Thames Water also said it was continuing to monitor river, reservoir and groundwater levels.
Image source, PA Media/University of OxfordBillie Jean King took part in the sweltering ceremony this afternoon
Tennis legend Billie Jean King has received an honorary degree from the University of Oxford during the sweltering temperatures on Wednesday.
King was one of nine recipients who received the prestigious honour during the Encaenia ceremony.
Image source, University of OxfordFormer Prime Minister of New Zealand Dame Jacinda Ardern was also honoured
The ceremony usually has a strict dress-code, but that was relaxed due to the ongoing heatwave - with jackets and gowns optional for those in the procession.
The university said it had also put additional measures in place to "help guests manage the heat".
Great Western Railway, external and Cross Country, external have extended their reduced service due to the heatwave to Friday and urged customers to only travel if essential.
Both rail operators said they would be running fewer trains and journeys would be slightly longer during the warmest periods of each day.
They added that customers can apply for refunds if they choose not to travel and tickets are valid for travel on alternative days.South Western Railway also extended their extreme heat measures earlier.
Image source, Getty ImagesToby Paine
Local Democracy Reporting Service
Image source, Portsmouth City CouncilHuge algae blooms that have spread rapidly in the hot weather covering much of a lake’s surface are set to be cleared.
Portsmouth City Council said the recent spell of extreme heat had rapidly accelerated the growth of green algae weed in the water at Canoe Lake, Southsea, Portsmouth
It said: “Our council maintenance teams regularly visit the lake to clear and clean as much as possible, however the current volume is making this difficult to maintain.”
Cleaning is done using a specialist craft that floats around the lake to cut and clear the algae.
Image source, Benedict Tufnell \ Henley Royal RegattaQualifying races for juniors at Henley Royal Regatta have been moved from Friday evening to Saturday morning due to the forecast heat.
The regatta said the decision had been taken "on medical and safety advice and in line with governing body guidance, with the welfare of competitors, staff and volunteers as the top priority".
It said all crews, coaches and officials were asked to check their race times, external carefully and follow the hot-weather guidance issued.
Tristan Pascoe
Political reporter
The owner of a bathroom shop in the New Forest has offered to let people come in and cool down.
Bath Granite and Marble in Lyndhurst posted the invitation on Facebook, saying that any elderly people struggling with the heat could pop in for a bit of respite.
Manager Sally Harbut said she did it while thinking of her own 90-year-old mother.
"Because we have so much stone, because we're a stone showroom, it's been so beautifully cool.
"I'm just conscious of how hot it is out in the High Street.
"I thought it'd be nice to let people know that whilst we're not a hospitality venue, they're welcome to come in, cool off, have a glass of water, maybe work for an hour or two if they want to, and just take advantage of the fact that this is probably one of the coolest spots," she said.
Image source, Met OfficeWeymouth Lifeboat Station has issued a warning as thunderstorms and strong winds are forecast to sweep in along the south west coast on Thursday evening.
The station said the weather was "certainly keeping us on our toes".
"The concern is the potential for dangerously strong winds. It is likely that these winds will develop suddenly, bringing with them stormy conditions which may not always be obvious from the beach and catch water users off guard."
The station advised those using watercraft including kayaks and paddleboards to be aware of the quickly changing conditions and to carry a means of calling for help.
It added during lightning, do not go in the water - if you’re already in, get out and find shelter immediately.
A Met Office, external yellow warning for thunderstorms comes in to force at 18:00 BST on Thursday.
Image source, Getty ImagesPlans for a power outage during the red warning for extreme heat have been postponed following concern from residents.
SSEN's to cut power to the properties in Chipping Norton, Oxfordshire between 09:00 and 17:00 BST on Thursday, were branded as "dangerous and reckless" by residents affected.
The company initially said the work was "essential" but in a letter distributed to residents on Wednesday, revealed it would postpone the outage.
"This process has been going on today, and owing to the temperatures which have actually been observed over the past few hours, and the increasing certainty of very high temperatures again tomorrow, a decision has been taken to postpone the planned supply interruption that was due to affect 31 customers on Thursday 25 June."
It said the work would be rescheduled at the earliest opportunity.
The Met Office has extended the red extreme warning into Friday for London and parts of south-eastern England.
It will be valid from 00:00 to 21:00 BST.
Temperatures are expected to remain in the low to mid thirties and with high humidity - it will continue to bring health impacts to the wider population along with transport disruption.
Image source, Met Office
Image source, SubmittedThirty-one passengers were led to safety from a hovercraft after its engines were seen smoking.
Hovertravel's Island Flyer was preparing to depart from Southsea on Wednesday evening on its regular route to Ryde on the Isle of Wight.
Fire crews were sent and the hovercraft's crew used the onboard fire extinguisher.
On Thursday morning Hovertravel said its crossings between Southsea in Portsmouth and Ryde on the Isle Of Wight were currently running as normal.
Thursday will be a hot and humid day with plenty of sunshine and little to no cloud cover expected.
Tonight will be predominantly dry and clear, however in the early hours there is a risk of a few scattered heavy and thundery showers.
Image source, SWRSouth Western Railway has extended its reduced service due to the heatwave to Friday and urged customers to only travel if essential.
Chief operating officer Stuart Meek said: "We are working hard to keep customers who need to travel moving, but the extreme temperatures mean we have to run a reduced timetable and there may be further short-notice changes.
“While it might be tempting to head down to the beach to enjoy the sunshine, we strongly urge customers to heed our advice to avoid getting stranded.
The rail operator said to help customers complete journeys, tickets are valid for travel on alternative days, with full details on its website, external.
Image source, Bournemouth PolicePolice say nitrous oxide is being used heavily by groups on Bournemouth Beach causing antisocial behaviour and disorder.
Bournemouth Police said officers had found the gas being "consumed on an almost industrial scale by groups on the beach".
The force said dealing with those involved saw more than 20 officers on patrol spend most of Wednesday dealing with large groups gathering on the beach.
It said their behaviour affects locals, families, and others trying to enjoy the beach.
Officers added that many of those involved were confrontational to officers and do not see a problem with using it, even though it is a Class C drug.
Possession of nitrous oxide became a criminal offence for recreational use in England and Wales in November 2023.
Here's a reminder of where the amber and red warnings for extreme heat are in the South.
They came into effect at 09:00 BST on Wednesday, covering much of Dorset, Hampshire, Berkshire and Oxfordshire.
The same warnings will come to an end at 23:59 today. A yellow warning for thunderstorms has been issued for south-west of England - that is due to last from 18:00 this evening to 23:59.
After they expire, a separate amber alert for extreme heat, covering south-east England, eastern England and parts of the Midlands will be in place until 23:59 on Friday.
A similar warning, covering a smaller area, will be in place until 21:00 on Saturday.
Image source, MET OFFICE
Searches are ongoing for a 15-year-old boy who was reported missing after last being seen swimming in a lake.
Testwood Lakes, near Totton, Southampton, was closed off as police marine units joined other emergency services in the search on Wednesday afternoon.
Hampshire Police said searches for the boy, last seen in the water at about 13:35 BST, were ongoing.
Image source, Network RailRail operators are urging people not to travel in the red warning area on Thursday, warning of disruption for those who do.
Network Rail said on Friday 26 June, passengers travelling to, from or within the amber weather warning area, external should only travel if absolutely necessary - while passengers outside of those areas should continue to check travel plans carefully.
It said trains will run but significant disruption is expected, with speed restrictions, amended timetables and a higher risk of delays and cancellations.
Image source, BBC Weather Watcher SolentgirlBBC Weather Watcher Solentgirl wouldn't have known they were photographing a record when they submitted this photo
The UK experienced its hottest June day on record after temperatures soared to 36.1C (97F) in Gosport, Hampshire, on Wednesday afternoon.
Wednesday's high came between 15:00 and 16:00 BST, breaking the previous June record of 35.6C recorded in Southampton in 1976 and Camden in 1957.
This new record is described as "provisional" by the Met Office, which now has to conduct checks to ensure the measurement is reliable.
With the heatwave set to continue on Thursday and Friday, the Met Office said it is possible the figure could be beaten again.
Image source, DWFRSFirefighters put out a blaze on one of their own fire engines after it went up in flames.
The crew were on their way to a call-out when the blaze broke out on the A350 at Charlton Marshall in Dorset on Wednesday evening.
Dorset & Wiltshire Fire and Rescue said nobody was hurt but the cab had been completely destroyed.
Image source, BBC Weather Watcher Dee CeeIt's Thursday and the heatwave continues with a rare red warning in place for extreme heat for a second day.
The Met Office warning, external remains in place until midnight with an amber warning for heat on Friday.
Provisional figures suggest the temperature reached 36.1C in Gosport, Hampshire, on Wednesday breaking the previous June record from the summer of 1976.
It could rise beyond that with an even hotter day ahead expected.
Schools and nurseries in the south remain closed or partially closed.
Rail operators have urged people to avoid travelling by train within the red weather warning zone and are warning those that do to prepare for a disrupted journey.