After months of rain, prepare for a mini-heatwave with parts of the country set to be as warm as Madrid by midweek.
The ‘warm and pleasant spell of spring weather’ by day comes despite a risk of chilly nights and frost.
The warmest conditions are expected on Wednesday, with 20C (68F) in parts of Wales and western England and 19C (66F) as far north as Manchester.
The hottest day so far was March 5, when 19.2°C (66.56F) was recorded in London.
After a damp start to the week with cloudy skies and rain, conditions are set to clear through tomorrow before things heat up.
It comes as spring blossom is bringing cheer to parks in towns and cities.
Dan Harris, chief forecaster at the Meteorological Office, said: ‘Wednesday looks likely to be the warmest day of the week for many, with high pressure dominant.
‘The warmest spots are likely to be in parts of west Wales and western England, where under sunny skies, 18-19C (64-66F), possibly even 20C (68F) is on the cards.’
He added: ‘This is due to the additional boost expected from the passage of east to south-easterly winds over areas of higher ground, known as the Foehn effect.’
The warmest spots could see temperatures on a par with the Spanish capital, where 20C (68F) is also forecast.
But Mr Harris warned there is still a risk of chilly nights, with a ‘big diurnal range’ this week – the difference between the maximum daytime temperature and minimum overnight temperature.
He said: ‘Thanks to the clear skies during the day, we’ll see some chilly nights after the warmer days with a few places experiencing air frost.’
The Met Office said settled weather is ‘expected to develop across the UK’ – although temperatures away from the west are expected to only reach the mid-teens Celsius.
As the milder air moves in tomorrow, temperatures could reach highs of 15-16C (59-61F) and 17C (63F) in isolated places.
The best of Tuesday’s weather is expected in the south and west of England and Wales, as well as around the Moray Coast, Scotland.
After the warmest conditions of the week on Wednesday, Thursday is set to be ‘dry and settled with plenty of sunshine, with temperatures cooling towards the seasonal average on Friday’.
Forecasters predict more settled weather, which could last for the rest of the month.
In a prediction for the rest of March, The Met Office said: ‘Under the influence of high pressure it will be a settled start to this period, with most places predominantly dry.
‘The odd shower cannot be ruled out in the southeast, and some rain may threaten the extreme north or northwest.
‘Temperatures will be close to or a little above average. In spells of spring sunshine, it should feel quite pleasant.
‘How long the settled conditions last is less certain, with some signals that showers / rain could return later in the period, most likely to the south.’
