A yellow heat health alert is in force across most of England and will remain in place until Thursday evening.
Temperatures are expected to climb as high as 31C (88F), bringing increased pressure on the NHS.
As the country swelters, here are some of the best ways to stay cool from forecasters and authorities across Europe, including the NHS.
Stay hydrated
It may seem like an obvious one, but drinking plenty of water is often overlooked.
Cool down from the inside out by staying hydrated with plenty of liquids. It is recommended to drink between 1.5 and 2 litres per day.
A dog cools off in the River Thames. Pic: PA
Taking cool baths or showers will also help you keep cool, according to the NHS.
Avoid alcohol
Bad news for some, but forecasters advise against drinking alcohol in the intense heat, as well as teas and coffees, which act as diuretics and can cause dehydration.
Read more: Find out the latest forecast for your area
Pyjamas in the freezer
During the day, place your pillowcase or pyjamas in the freezer. Take them out before going to bed. Hopefully they will cool you down and help you sleep better.
Throughout the day, wearing loose, cool clothing and a hat and sunglasses will also help.
And wearing lighter coloured clothes will keep you cooler.
…and flannels
Sticking a flannel in the freezer can be especially refreshing to place on your forehead as you lie in bed.
Turn on the fan
Fans can help your body regulate its internal temperature – and sticking a pan of ice cubes in front of it can make the circulating air even cooler.
If you haven’t got one handy, fill a hot water bottle with cold water instead.
Dump the duvet
Thin cotton sheets will absorb sweat and are more comfortable than duvets.
Your body temperature will begin falling during the night – so hopefully you won’t feel warm and uncomfortable for too long.
How to sleep better at night
It can be all too easy to start feeling annoyed and exasperated when you’re struggling to sleep.
The best thing to do is to try to distract yourself with a relaxing activity such as reading – and try going back to bed when you’re tired.
Avoid the temptation to go on your phone, as this activity can stimulate you.
Close windows
While it might seem counterintuitive, keeping windows closed and drawing the blinds during the peak heat will keep rooms cooler.
Open windows for ventilation when it is cooler outside.
Heat rises… so sleep on the lower floor
If your home has several floors, it might be worth sleeping downstairs. Spend more time in the coolest room in the house.
Plan ahead
If you are planning to spend time outside, plan your day to make sure you have plenty of food, water and any medications needed.
The NHS says that anyone vulnerable to the effects of heat should avoid the sun during the hottest part of the day, which is usually between 11am and 3pm.
Ensure you have sun cream, even if you aren’t prone to burning. Apply at least SPF15 with UVA protection.
Keep pets shaded
Owners may worry about how to keep their pets cool.
For starters, don’t keep them in the car and when home, the Humane Society advises keeping pets in the shade or air-conditioned area.
Apply ice packs or cold towers to their head, neck and chest.
Try this tip from the Royal Navy
Royal Navy officers have been submerging their hands in cold water to cool down faster since the 1990s.
Research has shown colder water speeds up the rate of cooling – with core temperature reduced by around one degree for every 10 minutes of hand immersion in 15C water.
This technique has also been adopted by athletes who need to cool down rapidly when alternating between rest and movement.
Pic: AP
Put ice on your pulse points
Applying ice to the wrists and side of the neck can help to lower body heat as the blood vessels in those areas are close to the skin’s surface.
