A surge of Icelandic air is set to hit the UK in the final 10 days of November and the beginning of December, with snow arriving and temperatures plunging to as low as -12C.
Forecasters said high pressure from the Atlantic and a trough over the North Sea and Continental Europe will be the main weather patterns during this period.
Northerly winds are expected around the country, with outbreaks of rain and snowfalls likely in Scotland.
BBC Weather forecaster Sarah Keith-Lucas said that after a mild start to this weekend, weather conditions will change over the next 24 hours.
She said: "It's turning much colder through the course of the weekend, November has been a mild month so far but things are about to change now."
This afternoon, northern areas will turn quite cool and blustery with a mix of sunshine and heavy showers, Ms Sarah Keith-Lucas said.
Southern areas will remain mostly cloudy and mild with some patchy rain in places, with temperatures remaining between 7C and 11C.
Tonight, most of the country will see clear skies but showers will continue moving in from the north.
Ms Sarah Keith-Lucas said: "Temperatures in most of our towns and cities will remain a few degrees above freezing, but expect a frost certainly in the most rural spots first thing tomorrow morning."
Tomorrow will be a sunny and dry day for most of the country, but it will feel rather breezy, forecasters said.
Next week will start on a dry note but on Wednesday, showers are likely to hit the South East.
Ms Sarah Keith-Lucas said it is now time to dig out winter coats as temperatures keep getting colder.
The Met Office warned of heavy snowfall in the north of the UK on Monday, with the cold blast predicted to reach the south by Wednesday night.
Most of the UK will see sub-zero temperatures with 0C expected in many areas, as well as lows of -7C.
Initially, southern England will not be as cold, but forecasters said by November 29 it is set to be freezing in London, drop to around -4C in Newcastle and in the Scottish Highlands it could get to -12C.
Met Office forecaster Marco Petagna said: "I couldn't imagine a better weather pattern for cold weather fans, with forecast models showing a northerly straight from the Arctic next week."
UK 5 day weather forecast
Today:
Dry and fairly cloudy across southern areas. Further north a band of mostly light rain moves southwards and reaches central areas by the end of the day. Showers follow the rain across north and northwest, falling as snow over hills.
Tonight:
Light patchy rain clears from southern areas. A rather cold northerly wind follows across all parts, mostly dry inland, but showers moving inland from north-facing coastlines.
Sunday:
Rather cold but dry and bright for most locations, however, showers will feed inland from the North Sea coastlines.
Outlook for Monday to Wednesday:
Initially settled and mostly dry with variable cloud cover. During Wednesday a band of rain moves southeastwards across northern areas, colder conditions and showers follow, showers wintry over hills.
