Sub-zero temperatures could bring the coldest night of the year to Scotland amid snow warnings for swathes of the country.

Arctic air will cause the mercury to plummet overnight on Thursday, with temperatures colder than -13C expected in parts of Scotland.

Heavy snow is also predicted to fall on Friday, with the Met Office issuing a yellow weather warning for much of the lowlands.

Areas that could be affected include Edinburgh, Glasgow, Stirling, Falkirk, Fife, the Lothians, the Borders, Lanarkshire, Ayrshire, Renfrewshire, East Renfrewshire, Dunbartonshire, Clackmannanshire, Perth and Kinross, Argyll and Bute and Dumfries and Galloway.

It follows weather warnings of snow and ice for much of Scotland overnight on Wednesday.

Met Office spokeswoman Nicola Maxey said: "The coldest temperature we have seen this year is -13C in Scotland and we are likely to see temperatures slightly below that.

"But we are not talking about those extremes in the town and city centres, it is out in rural areas, more exposed areas, particularly over lying snow where you see temperatures drop the most."

Above around 100 metres, 2cm to 5cm of snow is possible quite widely and above 250 metres, as much as 10cm to 15cm centimetres of snow may lie.

At lower levels, snow will be more variable with up to 3cm possible.

There is also a yellow warning for ice overnight in the north east, the Highlands, Shetland and Orkney, with showers of rain, sleet and snow likely to cause treacherous conditions.

The ice is expected to dry out over the course of Friday morning and will mostly affect inland areas as opposed to coastal areas.

Up to 2cm of snow could lie at around 100 metres above ground.

On Wednesday evening, three climbers had to be rescued from the Cairngorms mountain range after getting lost in freezing blizzard conditions.