The warm and sunny weather is to continue over the weekend and Britons are set to bask in temperatures of up to 20C, before colder and wetter conditions take over next week.
Temperatures are well above the average on Friday afternoon, with the mercury hitting 19C in the London and Birmingham areas.
However, the dry weather is contributing to high levels of air pollution, with “very high” levels recorded in the south east, and “high” levels across eastern regions, Greater London and Yorkshire and Humberside, according to the Government’s UK air index.
People, especially those with a cough or sore throat, are advised to reduce outdoor activities.
Moderate air pollution is to persist across the southern half of the UK on Saturday, with high levels still possible locally.
Looking ahead to the weather in the next few days, Met Office meteorologist Alex Deakin said: “It may well be the shortest weekend of the year, because the clocks go forward, but it will be one of the sunniest.
“It’s going to be blue skies almost across the board on both Saturday and Sunday thanks to a chunky area of high pressure that’s just wobbling around across the UK.”
Fellow forecaster Craig Snell told the PA news agency that despite some mist and fog on Saturday morning, it promises to be “the most widely sunny day across the country”.
“Temperatures will certainly be above par for the time of year, reaching the high teens, especially across parts of Wales and England.”
There could be a light breeze across southern England and a risk of isolated showers in the far north of Scotland, but blue skies prevail, with the clearest skies in the south.
On Sunday, when clocks go forward one hour at 1am, more sunny weather will usher in British Summer Time.
Some North Sea coasts could see fog and mist and eastern areas will experience more clouds which will subdue temperatures there, but elsewhere “we will again see another fine and dry day”, Mr Snell said.
Temperatures are widely expected to reach “15 to 18C, maybe 19 or 20 in one or two locations,” according to Mr Deakin.
Next week is expected to start with yet more pleasant weather, although with more clouds and the potential for a few showers in central and southern parts of the UK.
With a week of March still to go, the UK has already seen the amount of sunshine it would usually expect for the whole month.
Much of the country is also far drier than usual.
“Looking at March upon March, this March is certainly proving to be a dry and sunny one,” Mr Snell said.
Spring's a fickle season, it gives you one thing one week and then the next week it will give you something very different
But a cold air mass pushing in on Tuesday is forecast to bring unsettled and wet conditions and lower temperatures from the middle of the week.
Mr Snell said: “Next week will certainly be more on the cloudy side rather than the sunny side, and this time of year when we don’t have the sunshine, it’s not going to feel as warm.
“Certainly next week is going to be colder but it’s not looking like it’s going to be drastically, drastically colder”.
He added: “Certainly very different to this week, but it’s spring.
“Spring’s a fickle season, it gives you one thing one week and then the next week it will give you something very different, that’s what keeps us on our toes”.
Wintry showers are possible across the country, especially in the north and east, the Met Office said, though any snow will likely be limited to high ground in the north.
Chief meteorologist Paul Gundersen said: “Although the UK has had a good deal of fine and settled March weather in recent days, a change is on the way from the middle of next week with colder air spreading down from the north and the increasing likelihood of rain for most areas…
“With the influence of some unsettled weather, we’ll be seeing a marked drop in temperatures for most with colder air arriving from the north.
“This will see maximum temperatures drop into single figures for many areas, and below freezing overnight.”
The change in weather also diminishes the risk of air pollution, with levels expected to be largely low from next Tuesday.
Looking ahead to April, temperatures are expected to recover to average levels in the first days of the month, which looks set to be “less settled” and more changeable overall, Mr Snell told PA.
“We are probably going to be back to what people generally expect the weather in the UK to be like, every day different”, he said.
“Most places will probably see some rain which some of us haven’t really seen a lot of this week”.
