Brits could see the current unseasonal cold snap replaced with a new mini-heatwave, with highs of 22C at the weekend.
High pressure moving into the south of England will see temperatures slowly begin to heat up as the week goes on, before peaking on Sunday, according to forecasters.
While next week is set to be much drier for many as the calendar moves quickly towards the summer, with lockdown restrictions slowly being eased.
BBC meteorologist Ben Rich said high pressure is currently sitting to the west of the British Isles bringing isobars from the Arctic bringing in the unwelcome cold air.
But that pressure will begin to shift east and then southwards as the week goes on which will allow "some significantly warmer air" to move in, and Brits can "expect those temperatures to begin to climb".
Much-anticipated hotter temperatures will really take hold by Thursday and Friday with highs of 18C, before that things will remain fairly chilly with some rain.
Parts of Scotland will see daytime temperatures as low as 3C today and despite parts of England will reach 14C, that will be hindered by biting winds.
Mr Rich said by the weekend the high pressure will have moved through the north, leaving it exposed to frontal systems, but southerns can expect "a lot of dry weather".
"Some spells of sunshine and at this stage some warmer air starting to waft its way in. 22 degrees is likely.
"Further north temperatures recovering a little bit, certainly warmer than recent days but there's more chance across northern England, Northern Ireland and Scotland of seeing colder and some showery rain at times."
The forecaster said next week the high pressure will build its way back north meaning dry weather for more of the UK, though rain is likely in the north west.
This week has so far seen a return to cooler, "more springlike" weather, following the warm and sunny spells seen during the first half of the bank holiday weekend.
Temperatures on Saturday peaked at 24.9C in London, and remained widely into the 20s for many parts of the UK.
Sunday saw maximum temperatures drop by around 10 degrees across the country, with a cloud front moving southwards - though some southern parts remained warm.
The Met Office has said the increased cloud and wind in the coming week is "nothing significant or unusual" for this time of year.
Some parts of the UK can expect to see frostier mornings.
"Part of spring's charm is you can get both types of weather," a spokesman for the Met Office said.
"May can be quite a topsy-turvy month, getting closer to the start of summer. It's not unusual for spring to have a hot part and a colder part."
The return to duller weather comes following record-breaking April sunshine - with all four UK countries recording it among the top five sunniest since records in a series from 1929.
In the final week of the month, rainfall totals increased in many places - but the UK overall still only received 40% of average April rainfall, according to official Met Office figures.
UK 5 day weather forecast
Today:
Showers affecting northern parts, turning wintry across northern Scotland. Dry in the south with broken cloud and sunny spells. Cold in the north, but feeling less chilly in the south with lighter winds than yesterday.
Tonight:
Showers in the north and east, some wintry, becoming mostly confined to coasts. Clear spells developing, allowing a frost in places, sharp across parts of Scotland.
Wednesday:
Scattered showers for northern Scotland and eastern England, the odd one heavy, and still chilly. Dry with sunny spells in the south and west where a little warmer.
Outlook for Thursday to Saturday:
Some showers at times for the far north and northwest. Otherwise, many areas dry with long sunny spells. Still chilly by night, though feeling warmer by day in light winds.
