Temperatures successful a hamlet successful bluish Scotland dropped to -17.3C connected Friday - the UK's coldest January nighttime successful 15 years.
The mercury successful Altnaharra, which is successful the astir bluish portion of the Highlands, plummeted soon earlier 20:00, the Met Office said.
It is the coldest January overnight somesthesia since 2010, erstwhile temperatures dropped beneath -15C respective times astatine locations crossed the UK, including -22.3C connected 8 January successful Altnaharra.
Forecasters said they were not expecting it to autumn beneath -18C connected Friday but determination was a precise tiny probability it could scope -19C.
It was -14.5C successful Altnaharra connected Thursday night.
More than 50 schools were closed successful the Highlands connected Friday, with 13 unopen successful Aberdeenshire.
Hundreds of different pupils person besides had different time disconnected owed to closures successful Moray, Shetland and the Outer Hebrides.
What is forecast for the weekend?
Temperatures for ample parts of the UK are acceptable to autumn again arsenic the acold upwind continues.
Met Office meteorologist Alex Deakin said: "Friday nighttime into Saturday greeting whitethorn good beryllium the nadir of this existent acold spell."
Towns and cities successful Scotland could spot -2C to -5C and the Highlands whitethorn scope -14C oregon -15C.
The mean debased successful bluish Scotland for this clip of twelvemonth is astir 0.3C.
Met Office meteorologist Zoe Hutin said: "Certainly a acold nighttime to come, particularly for those beneath wide skies successful the eastbound and the northbound and successful agrarian spots arsenic well."
Cloud sum is keeping the temperatures from falling arsenic debased but it volition inactive beryllium chilly, Ms Hutin said.
Saturday is forecast to beryllium acold too, and Ms Hutin said: "We've inactive got contiguous to come, and time nighttime could besides beryllium chilly arsenic well.
"Temperatures for time night, it volition beryllium chiefly eastbound parts that spot temperatures dropping wide beneath freezing, truthful East Anglia, the north-east of England, bluish and eastbound Scotland arsenic well.
"So different chilly nighttime to travel connected Saturday, but past arsenic we spell into Sunday and into Monday, past we tin commencement to expect temperatures to retrieve somewhat.
"I won't regularisation retired the hazard of seeing thing astir oregon conscionable beneath freezing again connected Sunday nighttime into Monday, but it won't beryllium rather truthful melodramatic arsenic the temperatures that we're going to acquisition arsenic we spell overnight tonight."
Looking up to adjacent week, she said: "We're saying it's getting milder but by nary agelong does that mean (temperatures) are going to beryllium supra mean - it conscionable volition consciousness comparatively overmuch much pleasant than it is astatine the moment."
The UK has experienced a "particularly agelong acold spell", she said, adding: "It has been getting progressively colder each nighttime this week, whereas looking astatine erstwhile years, we've had possibly 2 oregon 3 days wherever things person been peculiarly cold."
Burst h2o pipes
Across the country, Scottish Water said it had recorded a 30% summation successful bursts connected its web of h2o mains, arsenic good arsenic pipes successful household and concern properties.
The institution said it expected a further summation implicit the play and into adjacent week arsenic temperatures autumn and past rise.
A spokesperson said: "We volition enactment to repair bursts connected our web arsenic rapidly arsenic imaginable and, though it is the spot owners' work to person bursts connected their spot repaired, we tin sometimes assistance with these.
"Scottish Water is monitoring the upwind conditions and its web astir the timepiece and has teams of engineers acceptable to beryllium deployed whenever needed."