Temperatures could surge to 26C in London on Wednesday, making the capital hotter than Barcelona, according to the Met Office.
Sunshine and warm weather will be felt across most of the UK, with Manchester and parts of Wales expected to see highs of 21C in the afternoon.
If temperatures hit 26C in London, it will be enough to surpass the hottest day of the year so far, which was 20.9C in Gogerddan near Aberystwyth on 18 March.
It will also mean many parts of the UK will be hotter than Barcelona which is set to reach 19C today.
Thursday will also bring sunshine to southern parts of the country, with temperatures in London forecast to hit 21C.
Met Office chief forecaster Paul Gundersen said: “We’re seeing a brief but notable spell of very warm weather for early April, with temperatures more typically associated with late spring or early summer. This could be the warmest spell at this point in April since 2020.”
It comes after Storm Dave brought snow and strong winds over Easter weekend, causing travel chaos and leaving homes without power as it swept across northern parts of the UK.

Gusts reached 93mph at Capel Curig in North Wales, while winds of 75mph were recorded at Emley Moor in West Yorkshire and St Bees Head in Cumbria, and one of 73mph was recorded at Buchan in Aberdeenshire, the Met Office said.
Some properties in Scotland were left without power following the high winds overnight. Scottish and Southern Electricity Networks (SSEN) fault response teams were out on the network working to reconnect the small number of customers affected, mainly in Skye, Caithness and coastal parts of Aberdeenshire.
Met Office weather forecast
Today
Often cloudy towards the north and west with some rain early on and again later in the day. Elsewhere, a fine day with plenty of sunshine and feeling very warm in places, especially across the south and east.
Tonight
A band of rain will move across Northern Ireland and Scotland overnight. Mostly dry for England and Wales with clearest skies in the east. A mild night away from northwest.
Thursday
Rain followed by cooler and showery weather will continue to move southeastwards across the UK throughout Thursday. Remaining dry and warm across the southeast until later on.
Outlook for Friday to Sunday
Unsettled throughout Friday and the weekend, with further bands of rain and showers. Some drier and brighter interludes developing in-between with temperatures near or occasionally a little below average.
Mapped: Where temperatures in the UK could reach 26C today
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