Britain has recorded its hottest day of the year so far, with temperatures soaring as high as 34C (93F) in London and southern England.

Shortly before 5pm on Saturday the Met Office said a temperature of 34.0C had been recorded in Northolt, west London, and Heathrow airport , approaching the all-time record for June of 35.6C, reached in Southampton in 1976.

🌡️Both Northolt and Heathrow have reached 34.0 °C today, not only making it the #hottestdayoftheyear but one of the warmest June days for the UK in around 40 years pic.twitter.com/A6iPbEQj0B — Met Office (@metoffice) June 29, 2019

Forecasters said the east Midlands and south-east England would experience the biggest jump in temperatures on Saturday, soaring into the mid 30s. The capital was hotter than Hawaii on Saturday afternoon, after temperatures exceeded 30C in Scotland and Wales on Friday. Pollen counts and UV levels were expected to be high or very high for most of the UK.

The Met Office meteorologist Alex Deakin said: “The vast majority of the UK will stay dry with sunny spells but the temperatures will be a talking point.”

At Glastonbury, where dozens of festivalgoers have been treated for heatstroke over the last two days, organisers have been handing out free sunscreen and advising people to drink sensibly. Temperatures were expected to climb to 29C in Somerset – where the festival is located – on Saturday.

Management at Lord’s cricket ground were also encouraging attendees to turn up with suncream, a hat and a water bottle for the Cricket World Cup match between Australia and New Zealand.

Western and north-western parts of the UK were forecast to be cooler and cloudier than in recent days – with temperatures likely to be around 22C on average. Outbreaks of rain and thunderstorms could hit eastern Scotland and north-eastern England later on Saturday.

The Met Office issued a severe weather warning for lightning in Northern Ireland and south-west Scotland on Saturday.

Warnings for #lightning and #thunderstorms have been updated, but what's the difference?



⚡️Frequent lightning causing power outages & some structural damage. Heavy rain possible but less of an impact



⛈️Thunderstorms with torrential rain & flash flooding. Some lightning possible pic.twitter.com/NaCB823j9q — Met Office (@metoffice) June 29, 2019

Meakin said Saturday night further south would be warm, humid and “tricky for sleeping”, but by Sunday a cold front would push building heat in the UK away and most places would return to more average conditions for June, including temperatures around the high teens and early 20s.

The UK experienced its previous hottest day of the year on Friday – with the temperature reaching 30C at around 3.50pm at Achnagart in Scotland.

Five people have died in the UK in recent days having drowned in open water. A 63-year-old man died in hospital after being pulled from the sea off the coast of Yaverland on the Isle of Wight on Friday night.

Another man died after getting into trouble around lunchtime on Friday in a cove between Helston and Penzance in Cornwall, despite the efforts of police, RNLI lifeboats and paramedics.

On Thursday, 12-year-old Shukri Yahya Abdi, was found by an underwater rescue team four hours after going missing in the River Irwell, near Bury in Greater Manchester.

Two men, aged 25 and 26, also died after being rescued from the sea off Torquay in Devon.

Temperatures in France on Friday climbed to 45.9C – nearly two degrees higher than its previous record – while Spain continued to battle wildfires as most of western Europe continued to swelter in the heatwave.

The heat has been caused by hot air pushing up from northern Africa, with Germany, Poland and the Czech Republic all recording their highest June temperatures this week.