As a low-pressure system moves eastward away from the UK today it allows cold Arctic air already in place for parts of Scotland, to spread south across the rest of the UK by early Tuesday.
Met Office Chief Meteorologist Jason Kelly said: “This week will see temperatures below average for the time of year for many. Blustery winds will become confined to the far northeast overnight, with winds falling light elsewhere.
“This will allow widespread frost by night, though in sunshine by day, it should feel pleasant enough.
“Wintry showers will continue across the northeast, becoming confined to Orkney and Shetland by tomorrow afternoon.”
From midweek low pressure begins to return from the southwest bringing outbreaks of heavy rain at times.
Although it will start to turn milder in the south it will stay colder in the extreme northeast with a few wintry showers.
Bank Holiday weekend weather
Looking ahead, Deputy Chief Meteorologist Nick Silkstone said: “It will potentially take until the end of the week for the milder air to push as far north as northern Scotland.”
As the milder air pushes in temperatures will once again trend upwards and be mostly a little above average by the bank holiday weekend, although still perhaps remaining nearer average in the extreme northeast.
Next week looks fairly settled at first, with a good deal of dry and mild weather that will be occasionally punctuated by the odd afternoon shower.
The Met Office has said that there is still far too much uncertainty in the forecast to give a detailed weather forecast for the Coronation weekend.