The hot, dry weather will be punctuated in dramatic fashion on Friday, with the risk of thunderstorms bringing up to 20mm of rain in an hour.
The Met Office has issued a thunderstorm warning - only the third since the new alert was introduced last month - for central southern England, the South West, the West Midlands, Wales and the North West of England.
Met Office meteorologist Martin Bowles warned people to be prepared for "flooding issues".
The warning, which runs between 11am and 8pm on Friday, says heavy showers will "most likely become thundery in places".
It adds that some of the showers are likely to cluster in slow-moving bands, "particularly over southwest England, with some locations receiving around 20mm in an hour".
Some places within the warning area will miss the showers altogether and have a dry day.
Despite the downpours, many parts of the country will still be very warm, with temperatures up to about 28C (82F).
Areas affected by thunderstorms could see temperatures fall to about 20C (68F).
The hot, dry spell will return over the weekend, with ex-Hurricane Chris expected to head towards Iceland, pulling more warmth across the UK.
Temperatures are forecast to reach 30C (86F).
Northwest Scotland will be cooler and cloudier, with some rain.
Next week looks a little more changeable than recently, with further slow moving thunderstorms expected on Monday and Tuesday.
England and Wales will be most at risk, with additional thunderstorm warnings possible.
Sky weather producer Joanna Robinson explained: "Before the introduction of the new thunderstorm warning, the Met Office would have used heavy rainfall warnings for the same situation.
"The aim of having a separate warning is to add clarity on the rainfall.
"Thunderstorms are hit and miss, whereas frontal systems in winter can bring prolonged heavy rain over a wide area.
"A thunderstorm warning will inform the public of intense rainfall, but that many places within the warning area will stay completely dry.
"It can also raise awareness of other hazards within a thunderstorm, such as lightning, hail and gusty winds."