Temperatures are set to plunge as low as -15C tonight in the UK tonight, making it the coldest night of winter so far.
Parts of England were still subject to ice and snow warnings on Wednesday morning, and the Met Office said further alerts are likely to be issued as the week goes on.
The mercury is set to drop sharply, with lows of -15C possible in Scotland and northern England overnight on Thursday and sub-zero temperatures expected across the country.
A temperature of -14C would equal the lowest seen in this month last year, recorded in Dalwhinnie in the Scottish Highlands on January 17 2024.
But 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 January 8 2010, according to Met Office data.
The UK Health Security Agency (UKHSA) has extended its cold weather health alert for all of England until Sunday.
Amber alerts issued on Thursday have been extended and will now run until January 12, meaning a rise in deaths is likely, the agency said.
Dr Agostinho Sousa, head of extreme events and health protection at UKHSA, said: “We are extending the duration of our Cold-Health Alert, since the Met Office are forecasting that the low temperatures we are seeing will continue further into this week, with snow and icy conditions likely to persist.
“This weather can have a serious impact on the health of some people, including those aged 65 and over and those with pre-existing health conditions, and it is therefore vital that we continue to check in on friends, family and neighbours that are most vulnerable.
“These people could be more at risk of heart attacks, stroke and chest infections as a result of cold temperatures.”
The Met Office yellow weather warning for snow covering southern counties of England remains in place until midnight on Wednesday.
Fresh flurries of snow could hit this area on Wednesday afternoon, with the possibility of up to 4in (10cm) over higher ground.
Meanwhile, weather warnings issued on Tuesday for snow and ice covering the Midlands, parts of North Wales, the North West of England, west and northern parts of Scotland as well as Northern Ireland remain in place until midday on Wednesday.
The country has been hit by widespread flooding in recent days and a danger to life flood warning was issued for Barrow upon Soar in Leicestershire as firefighters had to rescue dozens of people stranded in rising water.
Scores of flood warnings and alerts remain in place for England but more than 200 have been removed in the last 24 hours and the weather is set to be drier over the next few days.
One flood warning is in place for the River Wye at Monmouth and four flood alerts are in place for the rest of Wales on Wednesday, Natural Resources Wales said.
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