Sun-lovers are getting ready to crack out the sun cream and throw on T-shirts as temperatures rocket to 70F. A swathe of sweltering air carried on a warm weather front sweeping in from the Continent will turn Britain into a sultry steam bath.
However, the balmy spell will kick-off to a bang as tropical air crashes into cold air over Britain later today sparking heavy downpours.
And while forecasters say blue skies and sunshine will hold out through March, they warn an easterly wind may cool things down this weekend.
Today and tomorrow could creep towards March daily records of 22.8C (73.04F) recorded on March 16, 1961, in Bedfordshire, and 22.2C (71.96F) set in Enfield, London, in 1990.
Met Office meteorologist Alex Deakin said: “A warm front approaches from the south and there is some pretty warm air tucked behind it, and it’s the clash of the warmer air hitting the colder conditions that may spark some heavy rain in places.
“We could see some heavy bursts of rain on Wednesday, but that warm front is brining warmer air but if we see some sunshine temperatures could pick up.
“The weather system pulls away through Wednesday night and into Thursday, and a high starts to establish itself.
“Temperatures will start to pick up even in northern parts.”
Some forecasters say the mercury could nudge the 20C mark over the next 36 hours.
Netweather’s Ian Simpson said: “It will turn very warm for the time of year away from south and east-facing coasts, with highs of 17C to 19C in parts of England and perhaps even 20C locally.”
The warmest temperatures may be confined to southern and south-eastern regions although it will be widely warmer than average.
Jim Dale, meteorologist for British Weather Services, said: “In parts of the country we could see temperatures in the high teens by Thursday which is when we expect to see the peak of the warm weather.
“There will be a bit of a north-south split with cooler conditions away from the south.
“Warm air is coming in from the Continent brought in by high pressure.
“This high pressure may shift by the weekend, however, bringing cooler conditions from the east.”
While it may turn cooler from Friday, much of the country can still expect lots of blue skies and sunshine.
Mr Deakin said: “With high pressure sitting over the UK it means fine and sunny conditions over the weekend.
“Friday could be a bit breezy in places, and the breeze in terms of its strength and direction will play a big part.
“We could see a bit of an easterly breeze along the coast on Saturday, but it will feel very pleasant on Friday and into the weekend.”
Low pressure responsible for rain mid-week will eventually give way to high pressure through the next few days.
Most parts of the UK will see decent spells of sunshine and sultry temperatures ahead of the weekend.
John Hammond, meteorologist for weathertrending, said: “With a gentle breeze from a warming Continent, daytime temperatures will be on the rise through the teens. There’ll be some exceptions.
“The far northwest will be close enough to retreating weather fronts for cloudy, damp weather to linger on for a while.
“And on the other side of the country, grey, chilly skies may cling on over some eastern coasts exposed to the breeze.
“But for the majority, spring will be in the air.”
The Met Office warned heavy showers will sweep the nation later today spreading from central and eastern England into Scotland.
A spokesman said: “It will be cloudy for most of England, Wales and eastern Scotland today with rain at times, becoming heavier and more widespread later for central and eastern England.
“It will be brighter in northwest UK with some showers with brighter weather edging into other northern and western areas later.”