The Met Office predicts that Tuesday will see average temperatures of seven degrees - akin to a normal December day - with generally light, chilly winds.
These cloudy conditions will persist for most of the night with the possibility of rain, and minimum temperatures of three degrees.
The forecast for today and the rest of the week said: "Early mist, fog and any frost patches slowly lifting to leave a largely cloudy day. Most places staying dry, although there will be the odd spot of drizzle, this most likely over the hills. Winds generally light. Feeling rather chilly. Maximum temperature 7 °C.
"Largely cloudy conditions will persist overnight with patchy drizzle in places, and misty conditions across the hills. Generally light winds. Minimum temperature 3 °C.
"Largely cloudy but mostly dry at first on Wednesday, but a better chance of some brighter spells developing through the afternoon as the breeze picks up. The odd coastal shower possible later. Maximum temperature 7 °C.
"Thursday, occasional sunny spells, mostly dry, although some coastal showers. A brisk, colder wind. Friday, similar but winds lighter. Cold. Saturday, rain with some hill snow, moving east. Strong winds.