Temperatures are set to rise this week as the heatwave in the UK returns.
And while some people may love the sunshine and warmth, for others it can be a dangerous time.
The NHS says the main risks posed by a heatwave are dehydration; overheating and heat exhaustion and heatstroke.
Heatwaves can affect anyone but people most at risk are:
* older people, especially those over 75
* babies and young children
* people with a serious chronic condition, especially heart or breathing problems
* people with mobility problems – for example, people with Parkinson's disease or who have had a stroke
* people with serious mental health problems
* people on certain medications, including those that affect sweating and temperature control
* people who misuse alcohol or drugs
* people who are physically active – for example, labourers or those doing sports
The NHS has issued the following tips for people to stay cool during hot weather:
* Shut windows and pull down the shades when it is hotter outside. You can open the windows for ventilation when it is cooler.
* Avoid the heat: stay out of the sun and don't go out between 11am and 3pm (the hottest part of the day) if you're vulnerable to the effects of heat.
* Keep rooms cool by using shades or reflective material outside the windows. If this isn't possible, use light-coloured curtains and keep them closed (metallic blinds and dark curtains can make the room hotter).
* Have cool baths or showers, and splash yourself with cool water.
* Drink cold drinks regularly, such as water and diluted fruit juice. Avoid excess alcohol, caffeine (tea, coffee and cola) or drinks high in sugar.
* Listen to alerts on the radio, TV and social media about keeping cool.
* Plan ahead to make sure you have enough supplies, such as food, water and any medications you need.
* Identify the coolest room in the house so you know where to go to keep cool.
* Wear loose, cool clothing, and a hat and sunglasses if you go outdoors.
* Check up on friends, relatives and neighbours who may be less able to look after themselves.