Meanwhile, UV levels across most parts of the UK are expected to be high, except for northern Scotland where they will be moderate.
Some UV radiation is crucial for our wellbeing, enabling our skin to produce essential vitamin D, but too much can be dangerous.
UV radiation promotes skin cancer by damaging DNA in skin cells. Exposure has also been linked to eye problems.
You can also burn just as quickly when it is cloudy, and the sun is as strong this time of year as it is in August.
The NHS recommends spending time in the shade when the sun is strongest, using at least factor 30 sunscreen and reapplying it every two hours, and taking extra care with children.
High temperatures can also affect the body. To stay safe, the UK Health Security Agency recommends drinking plenty of fluids, staying cool indoors, and avoiding exercise during the hottest parts of the day.
