A level three heatwave alert is in place for south-east England as temperatures passed 32C (89F) in London on the hottest day of the year so far.
There will be high temperatures across most of central and southern England on Friday as hot air spreads from Spain, Portugal and north Africa, while Scotland, Northern Ireland and some of north England will face lower temperatures as a band of rain passes through.
The Met Office said the mercury reached 32.7C at Heathrow at 3.30pm on Friday, and could climb still further to 34C for parts of the south-east, where the Met Office predicts what might be the “hottest Royal Ascot on record” in Berkshire.
Stephen Dixon, a Met Office spokesperson, said temperatures in the low 30s were “not unprecedented, but it is unusual to see temperatures this high this early in the year”, adding that Friday’s temperatures would be the highest since summer 2020.
The temperature record for the year has been broken for the third consecutive day. The previous high of 29.5C was recorded at Northolt in west London on Thursday, which in turn surpassed the high of 28.2C at Kew Gardens on Wednesday. The heat would need to exceed 35.6C to break the record for the UK’s hottest June day, which was logged in Southampton on 28 June 1976.
Royal Ascot took the rare measure of relaxing its dress code on Friday, allowing men to remove their hats and jackets after the royal procession and letting spectators bring in their own water and soft drinks.
Dixon added that after Friday, “there is a shift on the way, with a cold front moving in from the north bringing a more unsettled feeling for many on Saturday”, with showers initially focused on central England and Wales before moving further south.
He said the far south coast of England would hold on to the highest temperatures longest, with up to 31C in places, which may meet the Met Office’s three-day criterion for a heatwave.
Ultraviolet radiation levels will be high, so the Met Office is recommending that people stay out of the sun during the hottest hours of the day and apply sunscreen.
The UK Health Security Agency (UKHSA) issued the level three alert across London, the south-east and east England to inform the NHS that it should prepare for possible increases in demand amid unusually high temperatures.
A level two alert is in place in the south-west and east of England, meaning health services should prepare in case there is an increase in temperatures.
Agostinho Sousa, a consultant in public health medicine at the UKHSA, told BBC Breakfast: “Right now the situation is stable and we expect the temperatures to drop tomorrow.”
The UKHSA advised people to drink lots of water, avoid physical exertion when it is hot, and keep an eye on vulnerable friends, neighbours and relatives as “people often don’t consider themselves at risk of dehydration and overheating”.
The guidance also suggests covering windows that directly face the sun to keep temperatures cool and to try to get air flowing through the home.