Parts of the UK will experience "notably warm" weather for this time of year, with temperatures set to reach highs of 27C (81F) today, forecasters have said.
The Met Office has said the highest temperature is expected in London, where warmer air from Europe will bring conditions that will feel "fairly unseasonable for many".
Check the weather where you are
However, the warm weather is set to be short-lived, with wet and windy conditions expected later this week, forecasters have said.
Met Office spokesman Stephen Dixon said that by Tuesday evening the UK will "start to see the arrival of rain to western areas, where some western upslopes could see rainfall totals of between 20 and 30mm of rain".
Mr Dixon said the temperature will remain "fairly high" on Tuesday night into Wednesday, with a minimum of 19C (66F) in some places.
He added: "An overnight low of 19C again would be notable for the time of year and could feel a touch uncomfortable for some, particularly as we're in late September."
Many areas of the country will experience a "fairly wet and blustery day" on Wednesday, with up to 10mm of rain expected in some places.
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The Met Office said that gusty winds of more than 50mph are possible, as well as a chance of "some very large waves for some western coastal areas".
It added that Thursday and Friday will be days of "sunshine and showers" and "mixed conditions", while more settled conditions are expected over the weekend as higher pressure builds.
The week promises "remarkable temperatures, big waves and a bit of heavy rain too", the Met Office said.
Wetter autumn than average
The forecast comes after warnings the UK could experience a greater risk of flooding and a wetter autumn than average, with strong conditions in the Pacific as a result of the El Nino phenomenon likely to cause adverse weather across Europe.
This year has seen the UK experience five separate heatwaves, with summer 2026 declared the hottest since records began in 1884.
A temperature of 30C (86F) or higher was recorded on 40 separate days, smashing the previous record of 34 days in 1995.
(c) Sky News 2026: 'Remarkable' temperatures expected in parts of UK as temperatures set to hit 27C
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