The heatwave took a day off in some parts of the country today, as cloud covered many eastern areas giving respite from the recent high temperatures.
Easterly winds brought overcast conditions to central and eastern England and east Wales with the mercury as relatively low as 19C in places.
However the hot weather blazed on further west and temperatures are expected to rise again over the next day or two in areas which were cooler today, with thunderstorms arriving during the week.
The hot weather has taken its toll on the UK, with grass fires in London, mountain blazes in the Welsh valleys and forest fires in Fife, Scotland.
The heatwave is believed to have caused up to 760 premature deaths already, and the British Red Cross has launched two call centres in Norwich and Ipswich to check on the welfare of hundreds of elderly and vulnerable people in the region.
Brendan Jones, a senior forecaster with MeteoGroup, the weather division of the Press Association, said: "Easterly winds have brought in cloud from the North Sea overnight. It's been over central and eastern England and east Wales, and conditions have been cooler, with temperatures in the order of 19 to 22C.
"Further west, it's a different story, with a good part of Scotland, west Wales, Devon and Cornwall, Northern Ireland and Ireland having very sunny weather and likely to see temperatures up to 29C."
Tomorrow will see a similar start in the east, though the cloud should clear away more readily than today, he said.
"From Monday to Wednesday it will be hot, and it is expected to be humid as well, which has not been the case so far.
"It's likely to reach 32 or 33C, particularly across the southern half of the country, on Monday and Tuesday, and we should look out for some lively weather, any time between Monday night and Wednesday. Some places are going to be seeing very active thunderstorms indeed, with a lot of lightning, and the possibility of flooding in a few places
"From Wednesday to the end of the week it will be less hot, though still quite warm, with some rain around."
The Met Office has warned of an "elevated risk" of fires in the countryside following six consecutive days of plus-30C temperatures and a dramatic reduction in the average monthly rainfall.
Police and fire chiefs have reiterated warnings about escaping the heat by swimming in open water after a number of deaths in recent weeks. Four people died in separate incidents on Tuesday in lakes, rivers and the sea in Norfolk, the Shropshire-north Wales border and Cornwall.
Officers in Lincolnshire reported another death yesterday afternoon, after a woman was pulled from the sea in Skegness.
Emergency services were called to the beach area behind the Beachcomber on Roman Bank, Ingoldmells, shortly after midday.
Officers said the 69-year-old woman's death was not being treated as suspicious.
Elsewhere, a four-week-old baby was among 10 children admitted to one hospital with sunburn since the period of hot weather began.
Six of the 10 patients - of which the oldest was 14 - needed specialist treatment after being referred to the Queen Victoria Hospital in East Grinstead, West Sussex, from other hospitals because of the severity of their burns.
In London, firefighters have tackled dozens of grass fires since Wednesday afternoon, including at Mitcham Common on Thursday when flames burned through grass and gorse in an area the size of four football pitches.
Insurers have warned wildfires could put lives at risk and cost millions of pounds in damaged crops and machinery.
Farmers have been urged to ensure that their fire extinguishers are well maintained and to reduce the risk of combine harvesters catching fire by regularly cleaning the machinery to remove chaff and dust.