Britain’s heatwave is about to begin with high temperatures hitting up to 24C (75F) today, the warmest day in the year. This will come before thunderstorms and heavy rain arrive tonight.

A lot of sunshine will hit the UK on Saturday. It’s expected to reach the South of England and the North of Scotland. This would make it a perfect day for barbecues, while there is a small amount of cloud in the North. 

Aidan McGivern from Met Office said it might be 16-19C (61-60F) broadly, with 24C (75F), the South East possible high.

This year, the UK’s hottest day was April 15. It occurred in St James’s Park (London), where it reached 23.4C (74.12F). 

However, the weather service warned the warm air is also likely to spark a few heavy showers.

Lauren Parkin and Sarah Holden enjoying the sun on Blackpool Beach, north-west England.

Widespread sunshine is set to be present from the north of Scotland to the south of England on Saturday, with just some patchy cloud in the North and West. Pictured: a swimmer at Bournemouth Beach in Dorset today

On Saturday there will be widespread sunshine from the North of Scotland to South of England, with only a few patches of cloud in the North or West. Pictured is a swimmer on Bournemouth Beach today in Dorset

Crowds are seen enjoying the sunshine at Bournemouth Beach in Dorset on what could be the hottest day of the year so far

Bournemouth Beach, Dorset is crowded with people enjoying the heat on the hottest day in the year.

Two joggers are seen on a sunny morning on Wimbledon Common in south-west London as warmer weather is forecast in the capital and the South of England

On a sunny day in South-West London, you can see two runners on Wimbledon Common. It is warmer than the forecast for the capital and South of England.

Sunseekers flock to Tynemouth Longsands beach in North Tyneside today as rising temperatures are set to make today the hottest day of the year so far

Because of rising temperatures, sunseekers are flocking to Tynemouth Longsands in North Tyneside this afternoon. Today will be the hottest day so far for the year.

The Met Office forecast parts of the South East to reach top temperatures for the week of 25C-27C (77-81F). Spokesman Richard Miles said 'at the moment Tuesday looks like being the warmest day of the week' (map showing temperatures today)

Parts of the South East are expected to experience the highest temperatures in the coming week at 25C-27C, 77-81F according to Met Office. Richard Miles, spokesperson said Tuesday “seems like the warmest of the weeks” (map showing temperature today).

McGivern explained that by Saturday evening the rains would have reached South West England, and had spread to southern England and Wales.

“In certain places it might just rain, but in central England, southern England, and on the coast, there are risks of heavy downpours and thunderstorms.

Sunday looks like another sunny day. Air from North Africa will bring above-average temperatures to the UK in May. However, it will be broken by thundery or heavy showers.

According to the Met Office, parts of South East will experience temperatures of 25C-27C (77F-81F) during the week. Richard Miles, spokesperson for Met Office stated that Tuesday appears to be the warmest of the week.

Some people will be able to enjoy sunny days throughout the week. However, heavy rains are expected across most of the country, especially in the North West and North.

They can be quite thundery in areas of central England or south-west Scotland.

People watch from Bournemouth Pier in Dorset, as people zip wire from the pier to the beach on Saturday afternoon

The people watching from Bournemouth Pier, Dorset as they zip wired from the Pier to the Beach on Saturday afternoon

Sunseekers flock to Tynemouth Longsands beach in Tynemouth, North Tyneside, with rising temperatures set to make today the hottest day of the year so far

Tynemouth Longsands Beach is a popular destination for sunseekers in North Tyneside. Today will be the hottest day so far this year, according to rising temperatures.

Two people are seen boxing at Tynemouth Longsands beach in Tynemouth, North Tyneside, on Saturday afternoon

Two boxers are seen on Saturday at Tynemouth Longsands beach near Tynemouth in North Tyneside.

A paddle boarder is seen in the sea off of Bournemouth beach in Dorset. Sunday is looking like another warm day, with air from North Africa bringing above-average temperatures for May to most places in the UK over the next week

The sea is clear for a paddle boarder as he paddles in Dorset’s Bournemouth. It looks like Sunday will be another hot day. The UK is experiencing above-average temperatures in May due to the air coming from North Africa.

People enjoy the warm weather at St Mary's Lighthouse near Whitley Bay in North Tyneside, Tyne and Wear on Saturday

People take advantage of the sunny weather at St Mary’s Lighthouse in Whitley Bay, North Tyneside. Tyne and Wear Saturday

People jogging on a bright morning on Wimbledon Common, south west London as temperatures are set to rise this weekend

A bright day for jogging at Wimbledon Common in south-west London, as the temperatures soar this weekend.

A warning to asthma sufferers about pollen 

According to a charity, rising levels of pollen this weekend can put asthmatics at high risk for life-threatening attacks.

Asthma and Lung UK stated that more than three million UK residents have lung conditions like asthma and chronic obstructive and pulmonary disease (COPD). They are also at higher risk of developing flare-ups and triggering attacks.

According to the Met Office, pollen concentrations are expected to be high in most parts of England and Wales. They will also predict medium levels elsewhere.

According to the charity, pollen may trigger symptoms like tightness in your chest, wheezing, and breathlessness for more than half (59%) of asthma patients and over a quarter of COPD sufferers.

An allergy can lead to tightening of the airways and sticky mucus that makes it more difficult to inhale.

Andy Page, Met Office chief meteorologist, stated that “The plume o warm air from the south will lead to higher temperatures in the entire country over the coming week.”

“However it seems like the Atlantic lows effects will stop sustained high pressure from the East.

“This is because, while there might be some warmer days (and in some places extremely warm) the week ahead will feel more like a May warm spell with heavy rains and some sunshine than it would hot summery weather.

The Met Office has also warned of the high levels of pollen in Britain, which may cause allergies sufferers to sneeze more over the next week.

Forecaster: Hay fever, which is commonly known as pollen allergy, is caused most often by grass pollens. However other pollens may also cause symptoms. These symptoms occur when the immune system responds to pollen to make histamine or other chemicals.

According to the CDC, hay fever affects approximately two percent of people. It is estimated that over 10 million Britons have it.

Asthma UK’s director of policy and research, Dr Samantha Walker said previously: “If you suffer from asthma, you need to check the pollen levels and forecasts for your area. Make sure that you keep your inhaler and what to do in case your symptoms worsen.

‘If you also have hay fever it’s important to use a steroid nasal spray every day together with non-drowsy antihistamine tablets as needed.’

Met Office chief meteorologist Andy Page said: 'The plume of warm air we have been expecting from the south will bring higher temperatures across the whole country over the next week.' Pictured: Branksome Beach in Dorset this morning

Andy Page, Met Office chief meteorologist, stated that “The plume o warm air from the south will bring warmer temperatures to the entire country over the coming week.” Photo: Branksome beach, Dorset.

The UK's hottest day so far this year was on April 15, recorded in St James's Park, London, where the mercury reached 23.4C (74.12F). Pictured: a swimmer out early enjoying the sunshine at Branksome Beach in Dorset

This year, the UK’s hottest day was April 15. It occurred in St James’s Park (London), where it reached 23.4C (74.12F). Pictured is a swimmer enjoying the sun at Branksome beach in Dorset.

Sunday is looking like another warm day, with air from North Africa bringing above-average temperatures for May to most places in the UK over the next week, but it will be broken up with potentially heavy or thundery showers. Pictured: two joggers on Branksome Beach in Dorset today

Sunday will look like another sunny day. Highs from North Africa are expected to bring above-average temperatures in most parts of the UK for May. But it’ll be broken up by heavy and thundery rains. Two joggers at Branksome beach in Dorset, today

However, the Met Office warned that a sun-kissed Saturday, which would be ideal for a barbecue, could be followed by heavy rain and thunderstorms. Pictured: The sunrise at Scarborough in Yorkshire today

But, heavy rains and thunderstorms could follow a sun-kissed Saturday that would have been ideal for barbecuing. Pictured: Today’s sunrise in Scarborough, Yorkshire

There is also a warning of high pollen levels in the UK by the Met Office which could cause allergy sufferers to sneeze a lot more in the coming week. Pictured: The sunrise on Glastonbury Tor, Somerset, early this morning

The Met Office has also issued a warning about high levels of pollen in Britain, which may cause allergic sufferers to sneeze more over the next week. Pictured is the sunrise at Glastonbury Tor in Somerset this morning

Sean Henry's Couple sculpture at Newbiggin-by-the-Sea is seen on the Northumberland coast during sunrise today. Temperatures are warming up for the weekend as most of Britain can expect to be bathed in sunshine

The Couple sculpture by Sean Henry at Newbiggin-by-the-Sea can be seen today on the Northumberland coastline during sunrise. As the British are expected to enjoy sunshine this weekend, temperatures will be rising.