The UK has recorded its hottest day of the year so far, with Heathrow Airport in west London hitting 28.6C (83.48F).
The previous high was 28.3C (83F) in Northolt in west London on 2 June.
The Met Office has warned people to be prepared when heading out and about due to high UV and pollen levels across much of England and Wales.
It is forecast to stay hot for the next few days before thunderstorms move in across England and temperatures become cooler.
Thunderstorm warnings are in place for the eastern half of Wales and much of England from Wednesday until Friday, with the Met Office saying there is potential for travel disruption and flooding.
Meteorologist Dan Stroud said: “We’re likely to become increasingly changeable towards the weekend.
“There is still the potential for some more settled spells and some warm weather is possible later in the month, but it is generally turning more changeable from this weekend.”
The Met Office had predicted Sunday would be the warmest day of the year but temperatures fell just shy, hitting 28C at Heathrow and St James’s Park in London.