The warning was issued this morning and motorists are warned that visibility levels will be extremely poor and to drive with extreme caution.
Thick fog will also cause travel chaos across the United Kingdom as commuters will face hard driving conditions and flight delays today.
There are also warnings that visibility will fall below 100 metres in places. "The heat rises and then it cools down and that is why you get fog forming".
Radiation fog is the result of clear skies allowing heat to "radiate" from the ground causing temperatures to drop rapidly and moisture suspended in the air to condense.
Motorists are advised to take care on the roads this morning as an orange weather warning for fog remains in place until 10am.
MET OFFICE/REUTERSRadiation fog is covering the United Kingdom but what is it?
Forecaster Helen Roberts said: "Mists will quickly develop tonight turning readily into fog, mostly across western areas".
Regions most at risk will be London and the southeast; northwest England; southwest England Wales and the West Midlands. The map below shows the warning zones.
Mr Wilson said: "There is a lot of radiation fog around at the moment".
Still remaining rather cold with highs of 6C. Lowest temperatures are expected to be 4° to 8°.
A Met Office statement said: "Frequent and heavy hail and snow showers are likely to affect many parts of Scotland and Northern Ireland from Monday evening, continuing for much of the day on Tuesday".