After weeks of wintry weather, many people should be able to put their hats and scarves away - as it is set to be the "mildest day of the year so far", according to forecasters.
Southern areas of England should expect temperatures of around 15C - although people in northern England, Scotland and Northern Ireland will not feel the heat quite as much, with temperatures remaining a bit lower.
Temperatures are expected to stay between 7C and 10C in Northern Ireland, and will be around 11C to 14C in Wales.
Billy Payne, forecaster for MeteoGroup, the weather division of the Press Association, said: "It is certainly looking very mild. I do not think we have had temperatures this mild this year so far. It could be about 15C. Essentially southern areas are going to see higher temperatures - London and perhaps East Anglia seeing 15C. Anywhere south of northern England is going to be in double figures."
However, Mr Payne cautioned: "But it will still be a bit colder in the north and Scotland."
He added: "It will be a pretty fine day - a good deal of sunshine and it will probably feel quite pleasant with the light winds and mild temperatures. We do believe it is going to be the mildest day of the year so far."
Meteogroup's forecast states that skies may turn fairly cloudy across Cornwall, while it will be largely dry with sunny spells across Northern Ireland and Scotland. The forecasters say it will be cloudy in north-west Scotland with a chance of "the odd spot of drizzle".
The outlook for Wednesday and Thursday suggests it will be cloudy across most parts of the UK with light, patchy rain. Although it may remain mild, it will be rather unsettled with showers or longer spells of rain for many.
It comes after a number of cold snaps with below average temperatures hit Britain earlier this year, which boosted sales of warm clothes and flu remedies. Heavy snow storms affected most of the UK in January causing severe disruption to schools and traffic and the deaths of at least nine people.
Persistent rain and a rapid thaw of snow and ice which followed went on to cause flooding in parts of the north and west of England.