Forecasters have warned that heavy rain could lead to flooding and travel disruption this week.
The Met Office has issued a yellow warning of rain for southern Scotland and parts of central Scotland, the Highlands, and Argyll and Bute which is valid from 2pm on Tuesday until 6am on Wednesday.
It states that occasionally heavy rain, and a thaw of snow lying on the hills, is expected to lead to localised flooding and transport disruption.
Later on Tuesday a yellow alert comes into force in southern and north-west Wales, with a warning of heavy rain between 7pm and 3am on Wednesday.
The Scottish Environment Protection Agency has issued 13 flood alerts around Scotland.
Police have advised motorists to check guidance for driving in adverse weather conditions.
The Met Office said: “Outbreaks of occasionally heavy rain, falling on to already saturated ground, during Tuesday and overnight into Wednesday are expected to bring some localised flooding across parts of western and central Scotland.
“Accumulations widely of 15-25mm are likely, with a few locations, mainly western hills, seeing as much as 50mm.
“In addition to the rainfall, rising temperatures will lead to a thaw of lying snow, especially over the hills and mountains to the north of the central belt of Scotland.”
The yellow warning covers Angus, Perth and Kinross, Aberdeenshire, the Stirling area, Dumfries and Galloway, the Borders, East Ayrshire, East Renfrewshire, South Ayrshire, South Lanarkshire and West Dunbartonshire, as well as part of Argyll and Bute and the Highlands.
It comes after heavy rain brought flooding and travel disruption in some areas on Friday.
The West Coast Main Line between Glasgow and Carlisle will remain shut for repairs until January 6 after flooding caused “significant damage” to an embankment.
In Wales, the Met Office warns that a spell of heavy rain is expected to develop through Tuesday evening but it should clear east early on Wednesday.
It warns people to expect some travel disruption and flooding overnight.