Temperatures in a hamlet in northern Scotland dropped to -18.7C on Friday – the UK’s coldest January night in 15 years.
The mercury in Altnaharra, which is in the most northern region of the Highlands, plummeted at around 22:00 GMT, the Met Office said.
It is the coldest January overnight temperature since 2010, when temperatures dropped below -15C several times at locations across the UK, including -22.3C on 8 January in Altnaharra.
The average low in northern Scotland for this time of year is about 0.3C, while for England, overnight lows are about 1.5C to 1.6C.
Temperatures had fallen to -14.5C in Altnaharra on Thursday night. The average low in northern Scotland for this time of year is about 0.3C.
More than 50 schools were closed in the Highlands on Friday, with 13 shut in Aberdeenshire.
Hundreds of other pupils have also had another day off due to closures in Moray, Shetland and the Outer Hebrides.
What is forecast for the weekend?
Temperatures for large parts of the UK are set to fall again as the cold weather continues.
Much of the UK endured below freezing temperatures into Saturday morning, with -11C recorded in Shap, Cumbria, and Heathrow recording -5C.
Met Office meteorologist Alex Deakin said: “Friday night into Saturday morning may well be the nadir of this current cold spell.”
Saturday is forecast to be cold too, and Met Office meteorologist Zoe Hutin said “it will be mainly eastern parts that see temperatures dropping widely below freezing, so East Anglia, the north-east of England, northern and eastern Scotland as well.”
High pressure is set to build across the UK over the weekend, leading to a significant thaw of snow and ice by Sunday and ushering in a warmer start to the new week.
Temperatures will slowly start to recover across western fringes of the UK, with central and eastern parts still likely to remain cold on Saturday and Sunday.
Scotland and Northern Ireland will see the quickest rise, with temperatures climbing to above average numbers for January by Monday.
This will lead to a significant thaw of all the snow and ice that may lead to higher river levels and a risk of flooding in places.
The UK has experienced a “particularly long cold spell”, Ms Hutin said, adding: “It has been getting progressively colder each night this week, whereas looking at previous years, we’ve had maybe two or three days where things have been particularly cold.”
Burst water pipes
Across Scotland, Scottish Water said it had recorded a 30% increase in bursts on its network of water mains, as well as pipes in household and business properties.
The company said it expected a further increase over the weekend and into next week as temperatures fall and then rise.
A spokesperson said: “We will work to repair bursts on our network as quickly as possible and, although it is the property owners’ responsibility to have bursts on their property repaired, we can sometimes help with these.
“Scottish Water is monitoring the weather conditions and its network around the clock and has teams of engineers ready to be deployed whenever needed.”