A two-day heatwave will help to extend the summer across the UK, with temperatures predicted to peak at 30C.
The mercury has been gradually warming over the last few days and will heat up to around 28C in central, eastern and southern England on Wednesday.
On Thursday, temperatures will climb a further point for much of southern England and could reach 30C in London.
James Wilby, a forecaster for MeteoGroup, the weather division for the Press Association, said it is too early to say if it will be the last of the summer sunshine.
"It's gradually been picking up over the last few days but today will be really warm. Most of England and Wales will see between 25C to 28C but London could reach 29C.
"London will see the best of the weather tomorrow too, possibly 30C. It will be cooler in Wales, in the north and in Scotland though.
"It's too early to say if this will be last of the hot weather this summer, as there's a chance we could get another wave of hot weather this month.
"But the closer we get to autumn the less chance there is."
The weather will take a turn for the worse at the end of the week with heavy rain expected across parts of the UK.
The hottest day of the year so far was August 1, when temperatures reached 33.7C (92.6F) at Heathrow Airport in west London, surpassing the previous seven-year high of 33.5C (92.3F) on July 22.