Becoming colder from the north, milder again from midweek

Not to be confused with the astronomical calendar when winter can start any time between the 20th and 23rd December, meteorological winter begins today. While it's a changeable and very mild start to December, it will be turning much colder from the North over Scotland and Northern Ireland tonight and across England and Wales during Monday.

Sunday afternoon sees cloud and showery rain over East Anglia and the South East moving away after dark. This will leave clear intervals, but they won't last, with bands of showers moving across the country from West to East overnight. For most, it will stay mild in South to South Westerly winds, which will be blustery in the West. Scotland and Northern Ireland will turn colder from the North, with showers becoming wintry on hills. There will also be a frost by Monday morning, chiefly in sheltered Highland glens.

The new working week begins with an area of showery rain across northern England working its way slowly South through the day, which should reach all but southern England by dusk. Ahead of it, it will continue to be relatively mild with some bright weather. But here too there will be a few showers, with temperatures between about 9 and 11C.

Further North behind the front, it will be noticeably colder, with showers over Scotland giving mainly hill snow in a blustery North West or northerly wind. Gusts in excess of gale force are likely along exposed coasts and towards Caithness and Moray for a time where it will feel particularly raw, with temperatures across the North getting no higher than 3 to 6C.

After dark, winds decrease and the showers, some of snow, begin to fade as a transient ridge moves across the country from the West. Clearing skies lead to a widespread frost with a few mist and freezing fog patches forming later, mainly across parts of Wales and in the West, as temperatures fall to between -3 and +3C. But the cold snap isn't expected to last, with increasing cloud and freshening southerly winds moving into Northern Ireland and the far West by morning.

Tuesday begins cold and frosty for most with some morning mist and patchy fog, but cloud will be increasing from the West, soon bringing outbreaks of rain to Northern Ireland. This will spread to Wales and the West, also perhaps to some central parts through the day, while further East it remains dry but cold. Temperatures, however, will be slowly rising in a southerly wind that will feel raw, before milder air arrives in the West, spreading to most parts overnight.

The remainder of the week then remains changeable with further rain at times. Temperatures will vary, but it will mostly be on the mild side for early December.