Temperatures have exceeded 30C in much of England and Wales – but rain is forecast.
Much of the UK has been experiencing another day of high temperatures – but the spell of extreme hot weather is due to come to an end with thunderstorms.
Rain and lower temperatures are forecast for Sunday in Scotland and Northern Ireland, spreading into parts of England and Wales on Monday.
A Met Office amber warning for extreme heat remains in place until midnight.
Experts have warned a lengthy period of rain would be needed to end the drought declared in parts of England on Friday.
A lot of land has been left parched and hard by the heat so rain is likely to hit the ground and run off – as it would on concrete – which could lead to flash flooding.
The extreme heat warning has been in place for a large part of England and Wales for four days – making it the lengthiest alert since the system was introduced last year.
It has not been as high as July’s heatwave – when recorded temperatures in the UK topped 40C for the first time and the Met Office issued a red warning for the first time – but the extreme heat has lasted longer.
The hot weather has seen several wildfires around England, from the North York Moors National Park to Dorset on the south coast.
Extreme heat warnings are issued based on the impacts of the weather conditions, rather than when specific temperatures are reached, the Met Office said. This means different conditions in different areas of the UK may trigger an extreme heat warning.
The heat warning only covered England and Wales but Northern Ireland experienced its warmest August day for nearly 20 years on Thursday while temperatures have been high enough in Scotland to cause a wildfire in West Lothian that has burned for several days.
But in Scotland and Northern Ireland, a yellow warning for thunderstorms came into effect on Sunday morning, due to last until the end of Monday as the north experiences a sweep of heavy rain for the next two days.
The warning then spreads to England and Wales across Monday and Tuesday, though the south west and south east of England face a third day of yellow warnings on Wednesday when northern areas are expected to be drier.
An official drought was declared for eight areas of England on Friday. The move is expected to trigger stricter controls on water use and five water companies have already announced restrictions, including hosepipe bans.
John Curtin, executive director of local operations for the Environment Agency, told the BBC “this is not a normal summer” and warned lack of water would be an issue for several months.
“We’ll need probably average or slightly above average rainfall this autumn into this winter for us to not be in a drought next year,” he said.
The agency has said there is enough water for public supply but has urged everyone to think about their water use.
In Surrey about 7,000 households were left with little or no water on Saturday because of technical issues at a treatment works.
The problem was fixed by Sunday morning but county councillor Liz Townsend told BBC Breakfast: “This is happening more and more now with warm weather.
“To be honest, the service is not fit for purpose now and residents are rightly getting very, very annoyed about what they’re having to put up with.”
- CHEAP DINNERS: Simple recipes that will cost you £1 a portion, or less…
- WASHING FRUITS & VEG: Do you really need to wash them before eating?