What a difference a day makes! Glasto revellers brave the rain after partying in 30C heatwave 24 hours earlier - as four-day heat alert for UK comes to an end today

Thousands of people attending Glastonbury Festival are braving the rain just hours after partying in scorching 30C temperatures. 

Photos show festivalgoers dressed in raincoats as rain showers hit the festival this morning.

It comes as the Met Office said Wednesday was the hottest day of the year so far. Forecasters said temperatures soared as high as 30.3C at Heathrow Airport while most of southern England was in the high 20s.

However, the mini-heatwave which swept much of Britain in the last few days is set to end. The UK Health Security Agency (UKHSA) has issued yellow heat health alerts across most of England until 5pm today.

While the south can expect refreshing breezes today, it will get 'unseasonably windy' elsewhere - with 30-35mph gusts in northern England and North Wales, and full gales in Scotland and Northern Ireland.

Temperatures are expected to be highest in London and Norwich at 25C. Further north, it will be much cooler with Manchester forecast to hit 20C while Inverness will hit 18C.

Paul Gundersen, a Chief Meteorologist at the Met Office, said: 'A cold front will sweep down from the northwest to the southeast over the next 24 hours, bringing with it cooler air and an end of the very warm weather many have been experiencing in recent days.

'A band of patchy rain, which could be heavy in the far northwest at first, will move east across England and Wales, bringing temperatures closer to average. 

'It will still be very warm in the far southeast on Thursday, but the cooler air will arrive by the evening, and then all places will enjoy a much cooler night than of late.'

Friday will be bright and breezy with showers in the north, heavier across Scotland, the Met Office said.

Meanwhile, the weekend will see plenty of warm and dry weather, especially in the south and east. 

The Met Office also said there will be some cloud and patchy rain or showers around, mostly across central and northern parts of the UK.

Yesterday's heat followed on from a top temperature of 30.5C in Chertsey, Surrey on Tuesday.

Meanwhile, the British Horseracing Authority said it was looking into whether hot weather played a part in the deaths of four horses at a Devon race meeting on Tuesday - the highest death toll in a single afternoon in six years. 

Happy Helen, Hallowed Rose, Bala Brook and Cuzzicombe all suffered fatal injuries during racing at Newton Abbot.

Looking ahead, the start of July will be dominated by 'changeable weather' - a mix of rain, cloud, dry weather and possible thunderstorms. 

The Met Office's long-range forecast from June 30 until July 9, said: 'The period is expected to be largely dominated by a changeable weather pattern with a mixture of cloudy, breezy and wet periods interspersed with drier, more settled periods and winds often from the west or northwest.'

'At first, a period of cloudy, humid weather is likely to be over, or clearing the south, bringing a small risk of thunderstorms before it does so. Following this, an area of rain is likely to arrive into the northwest, moving southeast, opening the door to the changeable weather pattern described above.'

The North West of England can expect 'frequent rain or showers' over the ten day period, and temperatures will be a little below to around average for early July.

Campers were pictured arriving at Worthy Farm in Pilton, Somerset in a bid to secure a prime camping spot. 

This year's event will see headline performances from global stars including pop singer Dua Lipa, British rock band Coldplay and American soul singer Sza, while Canadian country star Shania Twain will play the coveted legends slot.

The daughter of the festival's founder, Sir Michael Eavis, opened the gates of Worthy Farm to thousands of excited revellers as a brass band played and the sun shone down upon the fields.

Elsewhere, tourists cooled off by punting on the River Cam in Cambridge. Many headed to the picturesque Backs in the university city. 

It comes after the NHS said the number of people seeking heat advice on its website has 'skyrocketed' since a yellow heat health alert covering most of the country came into force on Monday.

Figures from NHS England, which runs the NHS website, show that on June 24 and 25 there were 28,116 visits to the heat exhaustion page, compared with 13,598 over June 22 and June 23 - a 107 percent increase.