Temperatures are unlikely to get much beyond 10C, with parts of the UK colder than Arctic Norway on Wednesday.
The maximum temperature is expected to be just 11C, far below average for the time of year.
Scattered showers and clouds will descend on Britain today as storms move in from the Atlantic Ocean.
The Met Office predicts most of the country will be chilly with some sunny spells.
Meteorologist Alex Deakin said: “Temperatures are set to rise over the next few days but first thing on Wednesday morning it’s far from warmer.
“Temperatures are still going to be below average for the time of year in many places”
Alex Deakin, Met Office meteorologist
“A chilly but bright start for many. Steadily things clouding over with rain and drizzle for quite a few.”
He went on: “As we start Wednesday it means it’s not as cold here but it is rather dull and drab.
“Brighter skies over eastern and northern England and indeed much of Scotland.
“Starting the day with some blue sky but it is a cold start here.”
Rain and drizzle are predicted to cover most of Wales and South-West England.
But in England, the weather will stay largely dry but cloudy.
Showers are expected across the Western Isles which will continue on and off throughout the day.
Alex added: “Temperatures are still going to be below average for the time of year in many places particularly where it’s damp and drizzly.
“A bit warmer than Tuesday but it’s not going to feel all that warm as the cloud slowly spills in through the afternoon.
“That cloud will continue to thicken and the rain and drizzle will spread into central and southern Scotland.”
This is predicted to spread to the east of England later on.
But the good news is a warm front will move in on Wednesday night, bringing more summery weather with it for Thursday.