The Met Office has issued a warning for dangerous fog across parts of the UK.
Two days of travel chaos are expected, today and tomorrow, with warnings in place.
The experts say they are expecting longer journey times and possible hazardous driving conditions, with delays to bus and train services also possible.
They added that visibility could drop to less than 100 metres, meaning flights could be cancelled or delayed.
A spokeswoman for the Met Office said: "Areas of fog, some of it dense and freezing, will develop during Monday evening and overnight, persisting into Tuesday morning in places.
"Fog will tend to lift into low cloud in many areas on Tuesday, though a few spots may stay foggy into the afternoon.
Image: Met Office
The Met Office have given an outline of what a yellow warning means for people: "many may be able to continue with their daily routine, but there will be some that will be directly impacted and so it is important to assess if you could be affected.
"Other yellow warnings are issued when the weather could bring much more severe impacts to the majority of people but the certainty of those impacts occurring is much lower.
"It is important to read the content of yellow warnings to determine which weather situation is being covered by the yellow warning."
The Met Office's weather warning is in place from now until noon on Tuesday.
Regions and local authorities affected
East Midlands
- Derby
- Derbyshire
- Leicester
- Leicestershire
- Lincolnshire
- Northamptonshire
- Nottingham
- Nottinghamshire
- Rutland
The Royal Liver Building surrounded by early morning fog in Liverpool. Picture date: Tuesday December 14, 2021.
Peter Byrne
East of England
- Bedford
- Cambridgeshire
- Central Bedfordshire
- Essex
- Hertfordshire
- Luton
- Norfolk
- Peterborough
- Southend-on-Sea
- Suffolk
- Thurrock
London & South East England
Peter Byrne
- Bracknell Forest
- Brighton and Hove
- Buckinghamshire
- East Sussex
- Greater London
- Hampshire
- Isle of Wight
- Kent
- Medway
- Milton Keynes
- Oxfordshire
- Portsmouth
- Reading
- Slough
- Southampton
- Surrey
- West Berkshire
- West Sussex
- Windsor and Maidenhead
- Wokingham
South West England
- Bath and North East Somerset
- Bournemouth Christchurch and Poole
- Bristol
- Devon
- Dorset
- Gloucestershire
- North Somerset
- Somerset
- South Gloucestershire
- Swindon
- Wiltshire
Ben Birchall
Wales
- Caerphilly
- Cardiff
- Monmouthshire
- Newport
- Powys
- Torfaen
West Midlands
- Herefordshire
- Shropshire
- Staffordshire
- Stoke-on-Trent
- Telford and Wrekin
- Warwickshire
- West Midlands Conurbation
- Worcestershire
Yorkshire & Humber
- East Riding of Yorkshire
- Kingston upon Hull
- North East Lincolnshire
- North Lincolnshire
- North Yorkshire
- South Yorkshire
- West Yorkshire
- York