The Met Office has issued an ice warning before temperatures plunge on one of the coldest nights of autumn.
Roads and pavements are expected to become slippery as heavy rain falls onto freezing surfaces in parts of Scotland, including Edinburgh and Aberdeen, from Wednesday night.
A couple of centimetres of snow could fall away from the coast across Aberdeenshire and Moray on a week when overnight temperatures have dropped to around -8C.
The Met Office said: "Scattered showers will affect much of the east coast of Scotland this evening and overnight, falling onto freezing surfaces.
"These will be heavy at times and will lead to a risk of icy surfaces where any treatment is washed off.
"Showers will be wintry above 200 metres away from the coast across Aberdeenshire and Moray, with 1-2cm of snow possible."
The ice warning is in place from 7pm on Wednesday to 10am on Thursday.
Meanwhile, the Met Office has issued a rain warning for parts of Wales and South West England.
Heavy rain will move in through the afternoon and evening and up to 30mm could fall within three or four hours.
Rain may turn to snow over higher routes in South Wales closer to midnight, with a few centimetres accumulating.
A separate rain warning will cover flood-ravaged towns between 9am on Thursday and 3am on Friday due to torrential downpours.
The East Midlands, South Yorkshire and Lincolnshire are included in the warning.
The Met Office said: "A period of heavy and persistent rain is likely on Thursday, 10-20mm is likely fairly widely within the warning area and a few places may receive 35-45 mm which may lead to further flooding and disruption.
"The rain is expected to ease and clear to the north later on Thursday night."
As of Wednesday morning, 34 flood warnings were in place, mainly in Yorkshire and the Midlands.
PM accused of doing nothing to help victims
Prime Minister Boris Johnson was accused of doing nothing to help flood victims as he took a break from electioneering to visit one of the worst hit areas.
One resident in flood-hit Stainforth in South Yorkshire told Mr Johnson: "I'm not very happy about talking to you so, if you don't mind, I'll just mope on with what I'm doing."
The woman, clutching a wheelbarrow alongside the troops sent to the area to help, added: "You've not helped us up to press. I don't know what you're here today for."
Another told him: "You've took your time Boris, haven't you?", to which Mr Johnson replied: "We've been on it round the clock."
Speaking to reporters at the scene, Mr Johnson said: "I perfectly understand how people feel and you can understand the anguish a flood causes.
"The shock of seeing your property engulfed by water is huge and also the anxiety of what may still be to come and I do thank the emergency services for everything they are doing."
Mr Johnson arrived in the area as nearly 100 soldiers began assisting communities cut off by the flooding.
The Government has announced a relief fund with £500 available to each eligible household.
Met Office five-day weather forecast
Wednesday
Cold start for Scotland.
Showers over some northern and western coasts but many places dry with some sunny spells.
Southwestern parts seeing more widespread rain during the afternoon with some gusty winds, particularly near coasts.
Staying cold.
Wednesday night
Rain over south Wales, with hill snow possible here, and southern England.
Showers feeding onto north and east coasts of England, Scotland and Northern Ireland.
Less cold than Tuesday night.
Thursday
Further rain for southern and southeast England, particularly southeast Wales and into Somerset, Bristol and Wiltshire.
Showers further north, mainly for coasts exposed to the strengthening northeasterly wind.
Remaining cold.
Friday to Sunday
Friday, bright in the northwest with a few showers, but cloudier with more frequent showers towards the southeast.
Over the weekend showers becoming more isolated with many places dry.
Cold.
