It comes as the Met Office has said heatwave conditions have now been met in eight parts of England.
The UK was as hot as the Mediterranean on Sunday as forecasters said the “historic” temperatures may break records for the hottest bank holiday Monday.
Britons saw the hottest day of the year so far on Saturday when temperatures of 30.5C were recorded in Kent, however Monday’s temperatures are expected to soar even higher to 34C in Greater London and across South East England.
It comes as the Met Office has said heatwave conditions have now been met in eight parts of England; Heathrow in Greater London, Benson in Oxfordshire, Brooms Barn in Suffolk, High Beech in Essex, Kew Gardens in London, Northolt in London, Santon Downham in Suffolk and Writtle in Essex.
The Met Office also said that Santon Downham was the first location to meet the criteria at around 11:30 and its heatwave threshold is 27C for three consecutive days.
It was closely followed by Heathrow at around 11:50, whose criteria is three consecutive days at 28C. Temperatures in that area have since climbed further to 30C.
Speaking to the Press Association, a Met Office spokesperson said: “We rarely see temperatures above 35C, even in the summer months, so to see temperatures getting close to 35 in May is, as I say, pretty historic.”
They added that overnight temperatures could also lead to records being broken, staying above 20C and being “uncomfortable for sleeping”.
Saturday was the first time this year that the UK had passed 30C.
The last time that happened in May was in 2012.
The exception is in the North West of Scotland where bank holiday Monday will be breezier and damper with thicker clouds.
Animals at London Zoo who are used to milder temperatures have been given ice lollies to keep cool in the boiling hot temperatures, a spokesperson said.
Predators are being fed blood-based ice lollies, otters are snacking on ice lollies made of frozen shrimp and crayfish and gorillas are hydrating on lollies made from fruit teas.
At Chester Zoo, Andean bears have been fed ice blocks to ensure they stay hydrated and keep cool.
Heat is considered to be more dangerous for older adults as their bodies struggle to regulate temperature and Age UK is recommending they stay inside during the hottest hours of the day, which are between 11am and 3pm, and have regular cold baths or showers.
Caroline Abrahams, Age UK Charity Director, said: “We can all help older people stay safe during periods of hot weather by checking in on older relatives, friends and neighbours to see if they need anything or are struggling with the heat.
“Offering to pick up shopping or medication, or even lending a fan, can make a real difference.”
The heat continues as people living in three villages in Kent have been experienced no water or low water pressure for the second day, BBC News reported.
The affected areas are Charing, Challock and Molash near Ashford, where people first reported water supply problems on Saturday evening.
South East Water (SEW) said the issue was resolved overnight, but added that water supply problems resumed at about 09:25 BST on Sunday due to “issues with the pumping station”.
The company has apologised to those who continue to be affected.
