In some patches of the UK, visibility will drop to fewer than 100 metres, leaving hazardous conditions on the roads for motorists.
The Met Office said the fog will clear in some areas, while northern areas will witness cloudy and pathy rain or drizzle throughout Sunday before the weather moves south.
Across the remainder of the country, conditions will be mainly dry with sunny spells, with several showers in the far north.
Tonight, patchy rain in the south will clear while clear spells and a few coastal showers take place in the north and east, the forecaster predicted.
