Drivers are being warned to take extra care on the roads as thick fog blankets much of the UK.
A yellow weather warning is in place until 11am on Monday, covering areas from York to Bath and most of the South East and eastern England.
The Met Office has warned of "difficult travel conditions," with visibility reduced to 50 metres or less in some areas.
Niamh Murray, operational meteorologist at the Met Office, described the conditions as the "perfect recipe" for fog.
Ms Murray said: "With autumn and winter and getting fog during this time of year, we get much longer nights, and that allows temperatures to fall away.
Monday will get off to a foggy start for some, with a patchy frost too Skies gradually brightening through the morning though https://t.co/37ZsxgT5gD
— Met Office (@metoffice) November 8, 2026
"We get a longer period of cooling and also the temperatures are much lower, so they're much closer to the temperature that we need for the air to become saturated and therefore form fog.
"Another thing that we need to form fog is quite light winds, not absolutely no winds.
"We just have the perfect recipe at the moment: light winds, clear skies, long nights, to allow that fog to develop.
"And particularly if we see the negative numbers (temperature in degrees Celsius), it can quite stubborn to clear the next day."
The warning follows a major incident on the M20 in Kent, where a crash involving more than 30 vehicles during foggy conditions left the motorway closed for nearly 12 hours.
Two people were seriously injured in the collision, which occurred between junctions 8 and 9 near Maidstone.
Edmund King, president of the AA, said: "Fog can transform a familiar road in a matter of minutes, so drivers need to be prepared to adapt their speed and leave more room between themselves and the vehicle ahead.
"One of the biggest mistakes is simply following the rear lights of the car in front.
"It can give you a false sense of security and means you may be travelling too close to react safely if that vehicle suddenly stops."
How to drive safely in dense fog
The most important thing to remember when driving in fog is to use your fog lights to make it easier to see and be seen in misty conditions.
The Highway Code states that motorists must use headlights when it isn't possible to see more than 100 metres in front of the car.
Drivers are also advised to use front or rear fog lights; however, this is optional.
AA top tips for driving in fog
The AA has also shared its top tips for when driving in fog.
- Use dipped headlights, wipers and demisters.
- Use fog lights when you need to.
- Beware of other drivers not using headlights.
- Only drive as fast as conditions allow.
- Slow down so you can stop in the distance you can see clearly and drive patiently.
- Allow 3 seconds instead of 2 between you and the car in front.
- Check your mirrors before you slow down.
- Open your window to listen for traffic at junctions if you can’t see.
Fog, cloud or rain? What's in store for the week ahead ❓ Find out in our latest forecast below 👇 https://t.co/ZTjJI4cgH5
— Met Office (@metoffice) November 8, 2026
It is also important to note that if you find it too foggy to drive and are finding it hard to concentrate, stop and avoid driving.
What does the fog light symbol look like?
The front fog light symbol shows a lamp with slanting lines of light in front of it, pointing left. The lines of light are intersected by a wavy line, which represents the fog.
The rear fog light symbol is the same as the front fog light symbol but in reverse.
The light and fog lines appear after the bulb, pointing right.
Share