Freezing temperatures as low as -3C will drape parts of the country in time for the re-opening of pubs, shops and outdoor attractions.
The Met Office has said Monday morning will be ‘another cold day for all’ but with pockets of sunshine in the north.
And there will be damp seats in many outdoor beer garden as showers will lash parts of the south and west throughout the day.
It comes as beer gardens and outdoor dining areas, non-essential shops, hairdressers, indoor gyms, swimming pools, nail salons and zoos in England are all open again for the first time since lockdown.
After a cold April weekend where many areas experienced a light dusting of snow, sub zero temperatures as low as -3C are expected in the morning across Britain.
Forecasters said that the day will start with a ‘widespread and sharp frost’ forming.
A Met Office meteorologist added: “Another cold day to come for all but lots of sunshine across Scotland and northern England but top temperatures coming in to around 7 to 11 degrees.
“As we go into Monday night it’s going to be another cold and frosty one.”
Heavy rain and hill snow is also forecast for Northern Ireland and west Wales early in the day.
The Met Office has said rain showers will move south-eastwards throughout Monday, lashing the Midlands by mid-morning before reaching the south coast by the afternoon and into the evening.
No flood warnings were in place on Sunday night, but the Environment Agency has issued six lower-level alerts for scattered locations in south-west England where flooding is possible.
Meanwhile, people in northern England and Scotland can expect to see a cold but sunny and dry start to the week.
Average midday temperatures range from 6C in the Scottish isles to 12C in Cornwall, with 10C forecast for London and 7C in Manchester.
A chilly night is due to follow on Tuesday, with freezing temperatures forecast across the UK.
The rest of the week is set to be cold but dry, the Met Office has said.
UK Weather Forecast
Southern parts of England and much of Wales starting rather cloudy with outbreaks of rain, sleet and some snow, this clearing through the morning, to leave sunny intervals and scattered showers. Elsewhere, sunny periods and isolated wintry showers.
Clear periods and a fairly widespread frost, although more patchy in the south and west, where some mist and fog will form later in the night.
Mostly dry with sunny spells in the morning after mist and fog patches clear, then a scattering of showers developing during the afternoon. Less cold than recently.