A yellow weather warning for fog has been issued for parts of England.
The Met Office warned of possible delays to journeys during the morning rush hour on Friday and flights could be delayed or cancelled.
The warning covers parts of the East Midlands, Suffolk, South East and South West and runs until 10am.
The fog will slowly clear and Friday is set to bring mild temperatures for many, with highs of 13C (55F) in London, 15C (59F)
in Leeds, 14C (57F) in Edinburgh and 16C (60F) in Aberystwyth.
Thursday was the warmest ever February day in Scotland, as Aboyne in Aberdeenshire hit a maximum temperature of 18.3C (64.94F) on Thursday afternoon.
It beats the previous high of 17.9C (64.22F) recorded in Aberdeen on February 22 1897.
Met Office forecaster Craig Snell said the mild weather is set to continue, but it is unlikely to reach such a high in Scotland again this month.
He said: "Aboyne at just before 1.40pm this afternoon hit 18.3C - that beat the previous record of 17.9C way back in 1897.
"A few stations don't report every hour so it may or may not go up, but we can say it's the warmest February day in Scotland on record.
"Over the next few days it'll be very mild temperatures, today is possibly the mildest for the next few days.
"It could be early next week until it's as mild again, though whether we'll see 18.3C is unlikely.
"So the mild theme is set to continue and it will be pleasantly spring-like through early next week."
Fellow Met Office spokesman Richard Miles said "a lot would have to align" for the UK-wide record to be broken.
He added: "It is unlikely from what we are seeing at the moment."