It comes after snow blanketed parts of the UK at the weekend, as forecasters warned it could cause travel chaos.
Brits woke up to single-digit temperatures this morning after they were expected to dip below zero overnight.
The Met Office said: “A cold start to Monday morning, with some freezing fog patches but also plenty of sunshine.
“Rain and brisk winds moving into the southwest.”
Forecasters added: “Another cold night for many, with a widespread frost and some freezing fog patches.
“Temperatures rising across the far southwest as the cloud and winds increase.”
They expected temperatures to plummet to -3C in Scotland and southern Wales, with the likes of London and Exeter looking to sit at 0C.
The Met Office warned of the chill after the mercury dipped to an icy -4.6 in Benson yesterday.
The forecast of rain comes as 40 flooding warnings remain in place by the Environment Agency, while there are 132 flood alerts.
Tomorrow is expected to be a wet one, too.
The Met Office said: “Rain across central and eastern areas mostly dying out, with sunny spells developing quite widely after patchy fog clears in central and southern England.
“Some showers developing in the west.”
The downpours are expected to soak Plymouth, Southampton, Cardiff and surrounding areas.
The rest of the week could bring warmer, drier weather, forecasters said.
Looking from Wednesday, it said: “Some patchy rain or showers across coastal areas on Wednesday, and Northern Ireland on Thursday.
“Otherwise largely dry and settled with some bright or sunny spells. Temperatures around average.
At the weekend heavy snow fell in parts of Cumbria, with many waking to a total whiteout.”
We had a little more snow than expected
Photos showed snow-covered paddocks, while cars navigated icy roads in Nenthead.
Snow coated the ground as far south as Longleat Safari Park in Wiltshire, where camels appeared out of place.
A yellow weather alert had been in place for a four-hour period on Saturday, covering parts of Gloucester, Worcester and parts of Wiltshire.
Met Office forecaster Simon Partridge said: “We had a little more snow than expected.
“It’s not unusual for this time of the year, we often do get some snow in March – it’s the old adage that it is more likely to snow in Easter than it is in Christmas, and there is a bit of truth to that.”
Heavy rain has also been falling across the country, with drivers seen making their way through floodwaters on Bognor’s Shripney Road.