New records for the hottest day in June have been set in England and Wales today.

But this heatwave is also bringing record-breaking nighttime temperatures.

Last night, the UK endured its warmest June night on record, as temperatures in Cardiff didn't fall below 23.5C.

Temperatures will cool slightly overnight tonight. But across much of England and Wales, it's expected to remain above 20C - what forecasters call a tropical night.

The London Ambulance Service says it saw a 50% increase in calls categorised as "immediately life-threatening" on Wednesday, compared to what it would usually expect on a Wednesday in June.

Within these life-threatening callouts, there were 33% more cardiac arrests than usual, chief executive Jason Killens tells the BBC, adding that the service is "exceptionally busy".

The London Ambulance Service has prepared for the rise in demand by putting an extra 400 ambulances out on the roads this week.

Calls related to serious conditions have seen the steepest rise, but Killens says "more people are fainting and feeling generally unwell in the street".

He tells the public to "help us help you" by trying to stay out of the sun at its hottest points, staying hydrated, and to avoid alcohol or at least drink in moderation.

While much of the UK has been sweltering, it's a different story in the Shetland Islands - where temperatures today have been closer to 15 or 16C.

"There are many, many brilliant reasons to live in Shetland, but the weather's not one of them," Joy Duncan, who lives in Scalloway, tells the BBC.

"And while my friends are cooking and melting in London, I've got my jacket on here! I'd love to be melting with my friends in Finsbury Park."

Rich Lancellot, who is on holiday from Florida in the US, says he's "happy to be in a cooler climate", with temperatures back home over 100F (37.8C).

Rachel Nutman, from the Late District in Cumbria, describes the Shetland weather as "delightful", and a "lovely temperature".

Image source, Getty Images

Wales has set a new temperature record for June, with 35.9C provisionally recorded at Cardiff's Bute Park at 17:00 BST.

In Northern Ireland, a provisional temperature of 30.8C was recorded in Castlederg, County Tyrone - breaking its record for the hottest day of the year again.

In England the provisional hottest temperature so far - in Merryfield, Somerset - has remained at 36.7C.

There was also no change in Scotland, where the provisional temperature was recorded at 31.2C in Threave.

Mark Poynting
Climate reporter

John asks: how can we have flooding reported only 72 hours ago, and now this morning we have a hose pipe ban inflicted?

As we reported earlier, South East Water has imposed a hosepipe ban for around 850,000 customers in Kent.

As John notes, it comes just days after parts of southern England were hit by heavy rain and thunderstorms on Monday.

South East Water has put the ban down to “high temperatures and record demand for water”.

But there isn’t a drought and the company acknowledged that reservoir levels were healthy.

This suggests that the ban is not down to a lack of available water, but difficulties in getting enough water to customers.

This will inevitably prompt further questions around the consequences of long-term underinvestment in the water sector.

Image source, UGC

There are plenty of ways to keep your home cool - one of the more inventive solutions is to paint your windows with yoghurt.

That is exactly what Emma from Hitchin has done, telling the BBC that the "difference is already noticeable and keeping the sunniest, hottest windows slightly cooler" .

Having painted her windows on Wednesday morning, Emma says her home is now 1.5C cooler than it was at the same time on Tuesday.

"Obviously external shading is more effective but not always feasible due to access, cost and availability of time and materials," she adds.

Emma says she chose this method because of an experiment that the BBC reported on last year.

At the time, Dr Ben Roberts, a senior lecturer in healthy buildings at Loughborough University, said the yoghurt can smell but only when it is drying.

Image source, UGC

The significance of today's heat record in the UKpublished at 17:23 BST

17:23 BST

By Becky Dale and Mark Poynting

Today’s record-setting June temperature of 36.7C is significant for a number of reasons.

It is now among the top 10 hottest days ever recorded in the UK and the only one to occur before July or August, according to the Met Office.

Climate change has made heatwaves more frequent and more intense in recent years, says the Met Office.

All 10 of the hottest days on record have happened since 1990.

And both of this year’s heatwaves have set records by dramatic margins.

The May heatwave peaked at 35.1C - more than two degrees above the previous recorded high for that month.

Thursday’s provisional record surpassed the 1976 June maximum by a full degree.

Climate scientists say these record-breaking margins are a clear sign of our warming world.

And while this heatwave continues, we may see more records fall.

Navtej Johal
BBC Midlands

Image source, Navtej Johal

Bill Gairns and Pam Nesbitt, both 75 and retired, are a couple living in a flat on the top floor of a 12-storey tower block in Worcester, England, which is under the red weather warning for extreme heat.

The pair, who are usually very active, say they can’t go out in the day because it’s "too hot".

Pam says, despite the usual advice, they’re keeping windows open in their home.

"Heat rises and we’re just cooked up here… We sit here, we have a towel and we mop our brows and we cope with it. We perspire or glow… not sweat!" she explains.

Meanwhile, Bill has found a novel way to stay cool: "I go to the toilet a lot, because the little toilet room is the coolest room in the house at the moment… it’s quite good, it’s quite nice, just go and hide."

Justin Rowlatt
Climate editor

Image source, Getty Images

Wow, big question. Let’s compress the entire history of our species into one short post - what could possibly go wrong?

We began as creatures of fire: cooking unlocked more energy from food and helped us grow bigger brains.

Farming came next. We learned to store energy from the sun in grain, but it also tied most people to grinding labour.

Then coal arrived: ancient sunlight - buried, concentrated and burnable.

Steam engines turned it into muscle. Oil turned it into movement. Gas became fertiliser and electricity.

Suddenly, modern life accelerated.

Fossil fuels have made us richer, healthier, more numerous and vastly more powerful. They've spread comforts once reserved for kings and nobles to billions of ordinary lives.

Think about it: our food, homes, phones, clothes, concrete, steel, ships, cars and flights all now depend on buried carbon.

The hard part comes next: how can we escape the fuels that built the modern world without giving up the world they built?

For a deeper dive into our “energetic” history and the climate challenge that faces us, take a listen to my Radio 4 series, A Pyrotechnic History of Humanity, on BBC Sounds.

Image source, Gemma Daubeney/BBC

Jersey has seen its hottest day since records began after 39.3C was recorded at Maison St. Louis Observatory.

One of the Channel Islands that is self governing, Jersey is not part of the UK.

Switzerland also exceeded its former record with a temperature of 38C recorded in Basel, according to the Swiss weather service.

A provisional temperature of 36.7C has been recorded in Merryfield, Somerset - making it a new record temperature for June in England.

In Wales, provisional temperatures hit 35.6C at Cardiff's Bute Park. That's also the hottest temperature recorded ever in June.

In Scotland, a provisional temperature of 31.2C was recorded in Threave.

And in Northern Ireland, it's provisionally been recorded as 30.0C in Castlederg.

These are the highest temperatures recorded across all parts of the UK this year so far.

Beth Rose
Disability affairs reporter

Image source, Getty Images

As temperatures rise, the effectiveness of medications can change.

The Medicines and Healthcare products Regulatory Agency (MHRA) says heat damage can break down active ingredients in medicine.

That can stop or alter how much the body absorbs when it comes to tablets, inhalers, hormone patches, insulin, blood glucose monitors and EpiPens.

Dr Alison Cave, MHRA’s chief safety officer, says some medicines can also make you more likely to "burn in the sun, feel dizzy, or get dehydrated", especially if you’re taking diuretics or have a condition like asthma, heart disease or diabetes.

She says most medicines need to be stored at temperatures below 25C - but cars, trains and even bags and pockets could get warm enough to cause problems and keeping them in a cool bag could be useful.

She adds: "If your medicine has changed colour, developed an unusual smell, changed texture, or looks different in any way, this could signal heat damage. Ask your pharmacist for advice."

Image source, Getty Images

With the hot weather comes the possibility of disruption to travel.

Today, a number of train lines are experiencing disruption after passengers in areas affected by the red warnings were asked to only travel if their journeys were essential.

Here's a look at the latest disruption:

On the trains

• Avanti West Coast is running fewer trains on some routes - with a reduction of one train per hour on Birmingham New Street, Manchester Piccadilly and Liverpool Lime Street routes
• The operator is also warning services running between Carlisle and Motherwell may be terminated at Preston
• Chiltern Railways are running reduced services on some of its routes while the CrossCountry network has cut some of its services including between Reading and York. There are also a number of cancellations on c2c services
• LNER has altered its timetable particularly affecting services to and from Leeds and to and from Lincoln
• Meanwhile, on the West Midlands Railway and London Northwestern Railway, trains are not running between Leamington Spa and Nuneaton - following a rail buckling in the heat - or between Liverpool Lime Street and Crewe
• Transport for Wales is running fewer services on some routes, while those between Chester and Wrexham General, between Pontypridd and Cardiff Bay and between Shrewsbury and Birmingham International are among those that have been cancelled until the end of the day
• AndElizabeth line services are not able to call at terminals at Heathrow Airport due to issues with infrastructure caused by the heat - meanwhile, Greater Anglia has cancelled a number of its services to and from Stansted Airport due to the "severe weather"

Image source, Getty Images

On the Tubes and Overground

There are minor delays on the District Line due to hot weather mitigation - other London Underground lines including Central, Circle and Metropolitan are experiencing delays due to train cancellations.

While on the London Overground, the Mildmay and Suffragette lines are seeing severe delays following an earlier signal failure.

Hospitals in England say their facilities are being stretched and equipment is being impacted due to the extreme heat.

Services at two hospitals in Stafford, the Royal Stoke University Hospital and County Hospital, have been "unable to operate at normal capacity in the heat and humidity".

The high temperatures are affecting operating theatres, testing labs and MRI scanners, according to the NHS Trust which runs both hospitals.

Meanwhile, a spokesperson for St George’s University Hospitals NHS Foundation Trust, which runs two hospitals in south west London, told the BBC its facilities are also under “extra pressure” due to the heat.

“Our ageing buildings weren’t designed for these temperatures, but we are doing everything we can to keep people safe and comfortable,” they added.

Matt McGrath
Environment correspondent

Anna in London says 1.5C of warming compared to pre-industrial times doesn’t sound like much, but this heatwave is way warmer above normal than that. Can you explain how these two connect?

You raise a very interesting and often confusing issue, Anna.

The 1.5C figure refers to a global average of temperatures compared to what they were before the industrial period began in around 1850 - when we started burning fossil fuels and adding greenhouse gases to the atmosphere.

The figure includes day and night temperatures from all over the world, from mountains to oceans and everything in between.

Essentially it is a long-term measure of the whole Earth's fever, not a reading of any one day in any one place.

A heatwave like the one we’re experiencing is the opposite: one corner of the planet, on land, in high summer, at the hottest point of the day.

So the two numbers aren't measuring the same thing, and there's no reason they'd match.

But a brutal heatwave can run many degrees above what's normal for the season, precisely because small changes in the global average can have major effects on our local weather - as we are now seeing in the UK and Europe this week.

Image source, EPA/Shutterstock

Anglian Water is urging customers to use less water as increased usage puts pressure on the company's network.

On Wednesday, it put a record 1,600 million litres of water in supply, which is a third higher than its typical distribution of 1,200 million litres.

Ian Rule, director of water services, says Anglian Water has "no plans to introduce a hosepipe ban", but higher-than-usual water consumption can lead to issues "such as bursts and low pressure".

"We're having to produce more water than ever before to keep everyone on supply, so we'd urge customers to avoid using hosepipes and use less water wherever they can," he says in an update posted to the company's website.

Michelle Roberts
Health editor

There are lots of things that you can do to cope with the heat:

If you are outdoors, stay in the shade and wear light-coloured loose-fitting clothing, ideally made of cotton or linen that allow air flow and let sweat evaporate. Wear high protection sunscreen and apply it often.

Stay hydrated by drinking plenty of water - around six to eight glasses or more. Diluted squash, fruit juice and iced-tea or coffee also count.

Keep your home cool. Close windows, curtains and blinds during the day and open them at night when the temperature outside has gone down.

Turn off any lights or electrical equipment that you don't need as they can make your home feel hotter. Electric fans can help though.

Babies who breastfeed should get all the water they need from breast milk and don not need any extra, the NHS says - but they may want to feed more than normal.

And take things slowly. Don't rush or do anything too physical if you are hot.

If you or someone else feels unwell with a high temperature during hot weather, seek medical advice.

Wales has recorded its hottest ever June day with a provisional temperature of 34.2C recorded in Bute Park, Cardiff.

Previously, the highest temperature for Wales in June stood at 33.7C - recorded in 2000.

It comes after the record for the hottest June day in the UK has been broken again after Yeovilton in Somerset recorded a provisional temperature of 36.4C - higher then yesterday's 36.1C in Hampshire.

We're looking through the latest set of provisional temperatures as a heatwave continues to grip the UK, stay with us.

Esme Stallard
Senior climate and science reporter

Lornawants to know: when will the UK roll out air conditioning across all infrastructure - including schools and transport?

Data on the percentage of homes with air-conditioning in the UK is limited - previous government estimates, external have put it at single figures.

But it is fair to say it is not the norm in the UK. We’re used to average summer temperatures of 16C., external

The UK Climate Change Committee (CCC) - independent experts that advise the government on all things climate - has recently estimated that 22% of homes in the UK will need some sort of "active" cooling measure such as air-conditioning in the future as the world gets warmer.

This issue has been hotly debated in politics recently.

The Conservative Party said there is a de facto ban on air-conditioning in new homes under building regulations. That isn’t quite true.

The regulations call for developers to consider all passive options first - i.e. things that will bring down the temperature without you having to do anything. This is to limit the use of extra energy.

Passive measures includes things like proper insulation, shading on windows, and increased green space.

Regulations have also been updated recently to reduce the amount of glass in new buildings to try and stop temperatures becoming unbearable in offices and homes.

At the beginning of the 21st century, glass skyscrapers were springing up across our cities. But it has been accepted that this has increased the risk of overheating.

Image source, Getty Images

Paul Kirby
Europe digital editor

Image source, Getty Images

Heatwave conditions that have left Spain, France and the UK sweltering are set to shift to the east in the coming days.

Temperatures in Germany could hit 40C in some western and south-western areas today, and across the country on Friday.

An extreme weather warning is now in place in much of the Czech Republic.

In France, which recorded its hottest day on Wednesday, Prime Minister Sébastien Lecornu announced the health alert level is being raised to its highest, to boost hospital staffing and protect the vulnerable.

Much of northern and southern Switzerland was put on maximum weather alert by MeteoSuisse, which warned of a "significant drought situation".

Although temperatures in Spain are set to peak at 38-39C in some areas today, forecasters say a cooler mass of Atlantic air is coming in.

An amber heat warning will remain in effect until 21:00 GMT in parts of England on Saturday, before temperatures cool on Sunday.