Temperatures are set to soar to 26C as the sunshine returns in time for the weekend.
The tail end of ex-hurricane Dorian, which caused death and destruction in the Bahamas, is expected to bring rain and strong winds to the north of the UK on Thursday.
But once this clears, the cyclone will combine with ex-tropical storm Gabrielle to bring strong winds that will push warm air across the country towards the end of the week.
Temperatures are expected to reach between 21C and 24C across the country on Wednesday.
Wednesday night is forecast to be dry with clear intervals for many, although there will be more cloud with showers at times in western Scotland.
After a bright and sunny start for most of England and Wales on Thursday, blue skies are expected to dominate in East Anglia and the southeast, where temperatures could get up to 22C to 24C.
By Sunday, temperatures could rise to 26C in parts of the UK and conditions should feel warm and humid.
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But while the days will become increasingly warm, the Met Office says there will be some chilly nights.
Much of the middle of September is forecast to be widely settled and dry with light winds and plenty of sunshine, especially in the south of the country.
However, there could still be some windier weather and outbreaks of rain in the north, particularly for northern Scotland.
Nicola Maxey, a Met Office spokeswoman, told The Independent: “We see the remnants of the tropical storm Gabrielle on Thursday bringing warm air.”
She added that it will be a “fairly good day for most people” on Thursday and Friday, and Saturday should see long sunny spells.
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“Temperatures on Saturday for London and the southeast could be 23C to 24C,” said Ms Maxey.
“We are looking at mid-20s on Sunday, 24C or 25C, or we might see 26C for London.”
Ms Maxey said the weather would not constitute a heatwave because temperatures have to hit 28C or above on three consecutive days in London, and 27C or above in southern and central parts.
The average temperature for the UK in September is 16C, she added.