Video report by ITV News Correspondent Rebecca Barry
The UK has seen its hottest August day since 2003 as temperatures soared to 36.4c at Kew Gardens and Heathrow on Friday.
Temperatures are forecast to rise further to 37C (98.6F) in London and the South East with a heatwave expected to blanket most of the country until Sunday.
The heat comes just a week just after the UK recorded a yearly high of 37.8C at Heathrow.
The warm weather is expected to last well into the night with temperatures staying above 20c until Sunday.
The threshold for a heatwave is three days of temperatures over 25C (77F) across most of the nation and 28C (82.4F) in London.
The coastguard has warned people to stay safe on beaches as the temperatures in the UK rose above Ibiza and Tenerife.
HM Coastguard said around 70 call-outs had been made by midday on Friday, which is “above average for this time of year”.
The Coastguard reported its busiest day for more than four years as it dealt with 329 incidents on July 31.
Matt Leat, head of infrastructure and technology lead at HM Coastguard, said this weekend could see a similar number of call-outs as families take advantage of the heatwave.
Speaking to the PA news agency, Mr Leat said: “The coast is very busy today and that’s grown across the morning and will continue to grow as the day goes on.
“Looking back to last Friday (July 31), we are going to hit that many number of call-outs potentially today and this weekend.”
Ishani Kar-Purkayastha, consultant in public health at Public Health England, said: “This summer, many of us are spending more time at home due to Covid-19. A lot of homes can overheat, so it’s important we continue to check on older people and those with underlying health conditions, particularly if they’re living alone and may be socially isolated.”
Elderly people are among the most vulnerable to hot weather, with advice telling them to contact neighbours if they are living alone, to try to stay indoors during the afternoon and to carry a bottle of water when out.
Caroline Abrahams, charity director at Age UK, said: “We want older people to continue to enjoy the warm weather but, if it becomes uncomfortably hot, we advise some sensible precautions, particularly for anyone who has breathing problems or a heart condition.
“It’s a good idea to remain indoors during the worst of the heat during the day. It’s also advised to wear thin, light clothing, drink plenty of fluids and to eat normally, but perhaps more cold food than usual, particularly salads and fruit which contain a lot of water and help us stay hydrated.
“We know that extreme heat can aggravate lung and heart conditions so our advice is to take care and if you are breathless, even after you have rested, to seek medical advice.”
Motorists looking to travel to seaside locations have been urged to ensure cooling systems are filled to the correct level, to look at the coolant date and to not overload their vehicle with luggage.
Breakdown experts Green Flag has predicted just under 127,000 breakdowns to occur between Friday and Wednesday, which translates to 15 breakdowns every minute.