Temperatures in London have hit 33.9C as a heatwave grips the capital.
The reading was recorded in Kew Gardens at 3pm and makes Tuesday one of the hottest days of the year so far.
The Met Office says the record UK high for June - 35.6C - could be broken with conditions expected to get even hotter later in the week.
Some 312 schools have closed across the country, with many London schools following suit to prepare for what could be an unprecedented heatwave for this time of the year.
It comes after a night of spectacular thunderstorms over the capital, which caused flash floods and thousands of lightning strikes.
London Fire Brigade said they took 400 calls and responded to two house fires believed to have been caused by lightning.
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COBR meeting to be held in response to the heatwave, the Government has said
A COBR meeting was held in response to the heatwave engulfing the UK, the Government said.
A red weather warning for extreme heat covering an area stretching from London to Swansea and Somerset to Birmingham was issued by the Met Office and will come into effect from 9am on Wednesday to 9pm on Thursday.
“We are working across Government and with devolved and local partners to respond to the severe heatwave,” a Government spokesperson said.
“As part of this response, the Cabinet Office held an official level COBR meeting on Tuesday morning, and will continue to closely monitor the situation.
“As well as being uncomfortable, the red weather alerts indicate that the heat poses a risk to life.
“We encourage people to pay close attention to guidance issued by the UK Health Security Agency, other public health bodies, and organisations such as transport operators.”
Mayor of London triggers 'high' air pollution alert for capital
Sir Sadiq Khan has triggered a “high” air pollution alert for the capital London on Wednesday on advice from forecasters at Imperial College, the third one this year.
He urged Londoners to stop their engines idling and avoid burning garden waste, which can contribute to high levels of pollution, and said details have been shared with London’s GPs and emergency departments, to ensure that they have crucial information to help vulnerable patients.
Deputy mayor for environment and energy, Mete Coban said: “Toxic air is responsible for thousands of premature deaths in London each year, which is why the mayor has done everything in his power to tackle it, which includes launching the world’s largest clean air zone.
“We are urging Londoners to look after themselves during this period of extremely hot weather and elevated pollution levels, stop their engines idling, and refrain from burning garden waste – all of which contribute to high levels of pollution.
“It is really important we all do our bit to protect those who are most vulnerable as we continue working to build a safer and greener London for all.”
How to sleep in a heatwave: 10 tips to cool down at night
London has been hit with its second heatwave of the year and, while the sun is always welcome, sleeping in the heat will prove more of a challenge. There’s tossing, turning and a whole lot of sweating.
Londoners have four tropical nights ahead of them from Tuesday to Friday, defined as when temperatures do not drop below 20C.
Tropical nights not only make it tricky to get some shuteye, but they can prevent proper recovery from the daytime heat, according to the Met Office.
So, as the heatwave takes a hold, here are some tips that can help you get through the sweltering nights.
Spanish-style ‘fire weather’ could create ‘capacity issue’ for forest keepers
Mediterranean-style “fire weather” will push the guardians of some of England’s largest forests to their limits if blazes break out, a senior adviser has warned.
Rob Gazzard, who advises the Forestry Commission on wildfires, said “extreme scenarios are going to be very challenging” to deal with for the organisation.
The Met Office has issued a red warning for “extreme heat” across parts of England and Wales on Wednesday and Thursday, covering several large cities such as London, Cardiff and Birmingham, as well as the rural Chiltern Hills, Cotswolds and Forest of Dean.
Temperatures are expected to climb to 39C or higher.
Temperature hits 34.6C
The highest temperature recorded in the UK on Tuesday was 34.6C in Wisley in Surrey, the Met Office has said.
Tuesday’s maximum temperature does not beat the June record of 35.6C set in Hampshire in 1976 and has not matched the 35.1C recorded on the hottest day of the year so far in Kew Gardens in London on May 26.
Heatwave warning after surge in number of children treated for sunburn in 2025
The number of children requiring hospital treatment for sunburn injuries surged last year, charities have said, as they warned of the growing dangers of heatwaves.
A “heat-dome” settling over western Europe could bring temperatures of nearly 40C to parts of the UK by Wednesday, with this latest heatwave expected to smash the record for June of 35.6C set in Hampshire in 1976.
A red weather warning for extreme heat covering an area stretching from London to Swansea and Somerset to Birmingham was issued by the Met Office from 9am on Wednesday to 9pm on Thursday.
As the Met Office’s weather alert was issued, the Children’s Burns Trust (CBT) and Royal Society for the Prevention of Accidents (RoSPA) warned of the growing dangers of heatwaves, which they said can cause serious harm to people, including heat exhaustion, dehydration and burns from prolonged sun exposure.
The charities warned children are particularly at risk during episodes of extreme heat, as “their skin burns more easily and they may not recognise early warning signs”.
In pictures: London's heatwave
Latest weather forecast
The Met Office has revised its forecast from earlier in the week, when temperatures were expected to go as high as 39C or even 40C.
London is not now forecast to get that hot, but the UK could see the record for the hottest day in June broken. The record currently stands at 35.1C.
A red warning for extreme heat is in place from the start of tomorrow until the end of Thursday.
Wednesday is likely to see a high of 35C and Thursday is forecast to hit 33C.
Friday could see temperatures rise to 36C before falling slightly to 32C on Saturday.
Things will then cool amid cloudier conditions, with Sunday forecast to see a high of 26C and next Monday 24C.
Will the heatwave affect Wimbledon?
The qualifiers for the main draw at Wimbledon is taking place this week. The Lawn Tennis Association has reminded fans to stay hydrated, wear hats, and apply sun cream.
Staff will also rotate more regularly to help shield those working the events from the sun.
Meanwhile, the women’s T20 World Cup is underway alongside the England men’s test against New Zealand.
Attendance is expected to drop because of the heat, particularly as schools will no longer attend the fixtures.
Extra drinks breaks have been introduced and the temperature will be regularly assessed to ensure it doesn’t pose a risk to players.
Thousands of pupils will not attend school during the heatwave
Thousands of pupils in the UK will either not be able to attend school this week or will head home earlier than usual because of full or partial schools closures amid the extreme heat.
Hundreds of schools have made decisions to either close completely, send children home early or make other adjustments such as relaxing uniform rules to help keep students and staff safe and comfortable.
It comes as a “heat-dome” settling over western Europe could bring temperatures of up to 40C by Wednesday, with this latest heatwave expected to surpass the record for June set in Hampshire in 1976.
