Climate experts link it to changing wind patterns.
Morning fog may reduce visibility on highways and farm roads, so drivers should take extra care.
Winds will be moderate, becoming stronger at times over open areas and at sea.
The days ahead
Light to moderate rain is possible in some areas, especially in the north and along the coast.
Forecasters expect temperatures to stay close to seasonal averages, with clear skies for most of the day.
Following the bulletins closely is the best way to be prepared.
The weather service advises following official bulletins for updates over the coming days.
Temperatures are expected to drop slightly at night, so a light jacket is a good idea.
