Emergency services across the country have shared advice to stay safe, cool and hydrated during the hot conditions - and warned against swimming in open water, after three people in the UK drowned in recent days.
The RSPCA has also urged people to call 999 if they find a dog left alone in a car.
For those stuck inland – including the thousands at the Glastonbury Festival in Somerset – shade was at a premium as queues grew at free water stations.
Festival-goers have been during conditions of 28.3C (83F).
Free sun lotion and a record number of water stations are just part of the contingency plans in place to look after the thousands of festival-goers who have gathered for the highlight of the music calendar.
Festival organisers moved to reassure music fans over fears of a water shortage, issuing a statement on Saturday afternoon stating there is not a lack of water on site.
It warned of long queues at some of the free water taps on site, asking people to find quieter parts of the festival zone to gather water. It also said it was restricting access to showers in a bit to conserve supplies.