Thunderstorms are set to strike parts of Britain with April showers expected across most of the country this week along with a dip in temperatures, say forecasters.
The Met Office said Monday's storms and heaviest rain are expected across parts of Wales, the Midlands and East Anglia, where the conditions threaten to disrupt travel.
Thundery showers could linger through the evening and become more widespread across Wales and England, with further spells of heavy rain on Tuesday.
Temperatures are likely to peak in the high teens, although it will start to feel colder from Wednesday, especially in the north, with overnight frosts.
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Rain was affecting the commute across southern and western parts of the UK on Monday morning, along with low cloud, mist and fog in places.
Visibility was down to about 100 metres (328ft) in southeastern areas, while it was breezy in Northern Ireland and frost was expected in the north after temperatures dropped to freezing.
The Met Office said: "Early low cloud will break leaving many fine and dry, although low cloud will tend to linger across the coast of northeast England.
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"Heavy showers and thunderstorms will develop though across parts of Wales, the Midlands and East Anglia."
The best chance of seeing sunshine will be in areas surrounding Cambridgeshire, which could see temperatures reach the late teens on Monday afternoon.
Rain is expected to move across areas in the Midlands, south-east England, north and east Wales and into Northern Ireland.
Areas in sunshine should be warm, although forecasters predict it will be chilly where cloudy.
In the evening, showers which could be thundery at times will become more widespread across Wales, the Midlands and southeast England, before moving southwards into the rest of southern UK, the Met Office said.
Elsewhere, it will be mainly dry with clear spells.
The Met Office warned that a band of heavy rain will move across England in the south on Tuesday.
Areas in the north of England and north Wales are expected to be sunnier.
More rain is expected in the south on Wednesday, but most places will be dry and bright spells are expected in the west.
It will feel colder, however, with nighttime frosts, the Met Office said.
Met Office five-day weather forecast
Monday
Early low cloud will break leaving many fine and dry, although low cloud will tend to linger across the coast of northeast England.
Heavy showers and thunderstorms will develop though across parts of Wales, the Midlands and East Anglia.
Monday night
Showers, still possibly thundery, become more widespread across Wales, the Midlands and southeast England, before moving southwards into the rest of southern UK.
Mainly dry with clear spells elsewhere.
Tuesday
Rather cloudy with rain, heavy at times, in the far south of the UK.
Elsewhere, largely fine and dry, although breezier and tending to feel a little cooler than Monday.
Wednesday to Friday
Rain at times in the south on Wednesday, otherwise mainly dry, with the west seeing the best of the bright spells.
Feeling colder, particularly in the north, with nighttime frosts.
