However, forecasters predict that the hot weather will continue next week after the stormy weekend.
Sweden has experiences their hottest summer for a century and Finland's usual summer highs of 18 degrees have been dwarfed by temperatures reaching 30 degrees.
The UK's current all-time record temperature for July stands at 36.7C, which was recorded at Heathrow in July 2015.
Lincolnshire is now in the yellow and amber warning zones Met Office
The highest recorded temperature in 1976 was 35.6C (96.1F) on 28 June in Southampton.
The mercury is forecast to hit 37C (98.6F) on Friday, with the possibility that the UK's all-time heat record of 38.5C (101.3F) will be broken, the Met Office said.
"Whilst many places are likely to remain dry, there is the potential for thunderstorms to develop during Friday afternoon, lasting well into the evening".
Scotland saw just 92mm of rain from June 1 to July 16 - down nearly half on the usual - Met Office figures show.More news: China's Xi opens BRICS summit in South Africa
The amber, or level three, warning is issued when temperatures are predicted to hit 30C (86F) during the day, and 15C (59F) at night, for at least two consecutive days.
Meanwhile authorities said the heatwave was causing "winter conditions" in parts of the NHS, while many nurses are said to be dizzy and exhausted.
The stormy weather is likely to spread across the United Kingdom over the weekend.
In the capital, London Fire Brigade called for a temporary ban on barbecues in public parks after a spate of grass fires, while Highways England demanded drivers refrain from throwing rubbish from their vehicles following a surge in fires by busy roads.More news: US Resisting Pushes by North, South Korea to End War
The RAC said it was expecting breakdowns to be about 15-20% higher than they would normally expect for late July, adding that breakdowns are already up 25% in London.
Health officials also said blood supplies have dropped because some people have been too dehydrated to donate, while others have chosen to stay in the sun.
A parliamentary environment committee has warned heat-related deaths could treble and rise to 7000 a year by 2050 unless the government plans ahead with strategies to protect people, especially the elderly.
The warning covers much of the East of England stretching up north.More news: No Mega Millions victor Friday; jackpot climbs to $493 million
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