People are being urged to stay hydrated, look out for vulnerable people, keep curtains closed and stay out of the sun in the middle of the day.
How likely are we hit 40c?
It is the first time the Met Office has forecast 40C in the UK, with the current record high temperature being 38.7C, which was reached at Cambridge Botanic Garden on 25 July in 2019.
The Met Office explained: “Weather forecast models are run numerous times to help us quantify the likelihood of a particular event occurring and estimate the uncertainty which is always present in weather forecasting to some degree. Some models are now producing a 50 per cent chance of maximum temperatures in excess of 40C in isolated parts of the UK for the start of next week. Mid, to high, 30s Celsius will be seen more widely with an 80% chance we will exceed the current record.”
Advice on staying safe from the experts
A Level 4 UK Health Security Agency Heat Health Alert has been issued for Monday and Tuesday. These are only used when a heatwave is so severe, or prolonged “that its effects extend outside the health and social care system”.
At this level, illness may occur among the fit and healthy, and not just in high-risk groups.
Dr Agostinho Sousa, head of extreme events and health protection at UKHSA, said: “Heat-health alerts have now been issued to the majority of the country, with temperatures set to remain consistently high throughout the duration of the weekend and the start of next week.
“It is important to keep yourself hydrated and to find shade where possible when UV rays are strongest, between 11am and 3pm.
“If you have vulnerable family, friends and neighbours, make sure they are aware of how they can keep themselves protected from the warm weather.’’
Mel Clarke, customer service director for operations at National Highways, said: “It is always important to plan ahead for your journey and this advice is no different during periods of hot weather. Our advice is that everyone should check their vehicles, such as tyres, coolant and oil levels, before heading out.” Find out more about driving in hot weather with National Highways.”
Government advice is that 999 services should be used in emergencies only; seek advice from 111 if you need non-emergency health advice.
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Met Office advice on staying safe during the heatwave