New weather warnings for “thick” freezing fog tonight and “icy patches” on the ground have been issued by the Met Office.
The yellow alerts cover East and South East England including London from 4pm on Tuesday until 2am on Wednesday.
Temperatures dropped as low -10C overnight in parts of the country after the mercury on Monday fell to -9C.
A minimum temperature of -4C is expected today.
In the warnings, the Met Office said: “Fog may cause some disruption to travel later today.”
It added: “Fog and freezing fog is likely to turn thicker and more widespread this evening and for a time tonight, although not everywhere will be foggy.
“Visibility probably improving slowly beyond midnight, as cloud and rain arrives.
“A few icy patches are also possible.”
The Met Office warned those in the areas affected to expect lower journey times by road, with delays to bus and possibly train services.
There is a chance of delays or cancellations to flights.
And slippery surfaces may lead to an increased likelihood of accidents or injuries.
North East Scotland is also under a yellow warning for heavy rain with a risk of flooding.
That alert has been in force since 6pm on Monday and will remain until 9pm on Tuesday.
December has seen temperatures drop below freezing across the UK and it’s not expected to get any warmer in the coming weeks.
Leading bookmaker Coral makes it 1-2 for this month to be the coldest December on record in the UK as temperatures plunge towards -10C.
The firm is offering 4-6 for this winter to be the coldest ever in the UK, while it is 4-9 that we will have a White Christmas this year.
“Large parts of the UK should see some snow over the next few days and with temperatures heading towards -10C, our betting suggests we are on course for the coldest December ever in the UK,” said Coral’s John Hill.
“Looking ahead to later this month, the probability of having a White Christmas is growing all the time. It may not just be the highlands which see the white stuff fall on Christmas Day this year,” added Hill.