The Met Office has issued a yellow weather warning which comes into effect at 4am for snow and ice which will hit London.
Forecasters are warning that snow is on the way which could turn “quite heavy” and could hit parts of Kent, West Sussex, East Sussex and Surrey.
For the Midlands, North West of England, South West of England and the West Midlands an amber cold health alert has been issued until Friday.
In the early hours of Monday morning temperatures will fall to almost zero and the Met Office said that a “mix of sleet and snow showers” will close in.
Sky weather presenter Jo Wheeler said, “At this time of year, clearer conditions with light winds are likely to result in overnight frosts, fog and icy stretches on roads and pavements.
“Today, we’re seeing a cold pool of air moving into southern areas with the potential for overnight showers to fall as sleet or snow over the higher ground.
“With night-time temperatures close to freezing, even in the towns and cities, there’s also a risk of showers falling on frozen surfaces and turning instantly to ice.”
The amber cold-health alert “means cold weather impacts are likely to be felt across the whole health service for an extended period of time, with potential for the whole population to be at risk.”