Temperatures in some parts of Scotland could plunge as low as -20C overnight as the cold snap continues.

Forecasters also predict Thursday could see the coldest January day for more than a decade.

A 36-hour Met Office yellow warning for snow and ice for the north and north east of the country is in place until midnight on Thursday.

More than 50 schools in the Highlands were affected on Wednesday, with most closed for the day due to snow and ice on roads.

A handful of schools in Aberdeenshire were also shut while dozens more opened later.

The latest warning, which took effect at 12:00 on Wednesday, states up to 15cm of snow could accumulate on high ground in the north and north east of the country.

The Met Office said: “Sleet and snow showers will continue for the rest of Wednesday and Thursday, before dying out by the end of Thursday evening.

“North-west Scotland and the Northern and Western Isles will see the most frequent showers on Wednesday, before extending to the north east on Thursday.

“Further accumulations of 3-7cm are expected to low levels, with 10-15cm possible above 150 metres.”

In places that are still experiencing snow cover, it could be as cold as -14C to -16C on Wednesday night.

But on Thursday snow fields may see temperatures between -16C and -20C.

A temperature of -16C would be the lowest recorded in January in the UK for 15 years, since -22.3C was logged in Altnaharra in the Highlands on 8 January 2010, according to Met Office data.

Tuesday night widely fell below freezing, with most of the UK waking up on Wednesday to a frost.

The lowest temperature overnight was recorded in Tulloch Bridge in the Highlands where the mercury dropped to -7C.

The lowest temperature this year came over the weekend when a low of -13.3C was recorded at Loch Glascarnoch in the Highlands.

Last winter the coldest temperature, -14C, was recorded in Dalwhinnie in the Highlands.

But the last time the UK had any temperature below -20C was in February 2021 when Braemar in Aberdeenshire plummeted to -23C.

Meanwhile, a number of weather and flood warnings are in place in England and Wales.

An amber cold health alert – the second-highest level – covering all regions of England, is also in place until midday on Sunday.

Network Rail said teams are working across the country to keep railways open by taking steps such as applying de-icing fluid to the junctions that allow trains to change tracks.

On X, formerly known as Twitter, a spokesperson said: “It’s been a challenging week, particularly for teams in the north who’ve kept services moving in some awful conditions.

“They’re well prepared for this extreme cold snap – the temperatures forecast may cause disruption, but we’ll do all we can to prevent it.”

ScotRail advised the cold weather may cause disruption to some services and passengers should check before they travel.

It also warned passengers to take extra care getting on and off trains due to the icy conditions.

On Wednesday, 54 schools and 39 nurseries in the Highlands were closed while in Aberdeenshire nine schools were shut.

Turiff Primary School will remain closed on Thursday with some other schools have already announced delayed openings.