Freezing Arctic air will bring the coldest day of the year so far to parts of the UK with warnings in place for snow and ice.
Chilly northerly winds will make the dip in temperature feel more like -4C in parts, according to forecasters.
As a result, Monday will be the coldest day of 2023 so far for many parts of the UK.
Areas affected by the weather warnings could experience power cuts and travel disruption, while some rural communities may be cut off by the freezing conditions.
It comes after the UK Health Security Agency (UKHSA) issued a cold weather alert for all parts of the country and highlighted the risk to vulnerable people in the North, which will bear the brunt of the severe conditions.
The warning will remain in place from early on Monday through to midnight on Thursday.
According to the Met Office, the wintry cold snap is due to "an Arctic maritime airmass" sweeping across the UK as an area of high pressure, responsible for recent milder conditions, moves away to the west.
Senior meteorologist at the Met Office, Craig Snell, said: "Going into next week we do see a bit of a change with even colder air coming through and then an increase in risk of sudden disruption due to some sleet, snow and some ice.
"So at the moment, the main focus is across northern and eastern parts of the UK where we have issued warnings already for Monday and Tuesday for the risk of some snow showers moving in from the North.
"Highest accumulations will be across the high ground. But even at lower levels, we are likely to see some disruption in places as the showers come through."
He added: "Scotland and some eastern parts of England have warnings going throughout Monday and Tuesday. In other parts of the country, we are keeping a close eye on it, there is a chance that we could see some snow further south as we kind of go through the week ahead.
"Some uncertainty still on where that snow is going to be because at the same time we will be seeing a milder air trying to come in from the Atlantic.
"So some places may well see some rain and other places may well see some snow."
Dr Agostinho Sousa, head of extreme events and health protection at UKHSA, said: "During periods like this, it is important to check in on family, friends and relatives who may be more vulnerable to the cold weather, as it can have a serious impact on health.
"If you have a pre-existing medical condition or are over the age of 65, it is important to try and heat your home to at least 18C if you can."
Temperatures are likely to stay well below average for much of next week, said the Met Office.
It comes after England had its driest February in 30 years.
The UK saw less than half of its average rainfall for the month, at 45%, with just 43.4mm.