Music fans could enjoy the hottest ever Glastonbury Festival, with temperatures potentially reaching 10C higher than usual, forecasters say.
The weather is expected to stay dry in the lead-up to the weekend, with a 20% chance of "isolated showers" on Wednesday and Thursday.
A "wedge" of hot air from France could blow over to the Somerset site on Thursday, resulting in sizzling temperatures of more than 30C.
Glastonbury's infamous mud could make an appearance at the weekend though, when the weather is expected to be "changeable".
The 900-acre festival site, being headlined by Radiohead, the Foo Fighters and Ed Sheeran, will host a population of 200,000 during the event.
"It is mainly going to be dry, looking at the whole event," a spokeswoman for the Met Office said.
"Wednesday, Thursday and Friday look dry with good spells of sunshine.
"The temperatures are expected to be in the mid to high 20s for all three of those days.
"Normally for that time of year, you would expect temperatures of 19 or 20C for Glastonbury, so it is going to be rather warm.
"People should take care in the heat, drink lots of water and take sun cream with them."
The Met Office spokeswoman said temperatures were expected to fall by the weekend, feeling "cooler and fresher" on Saturday and Sunday.
"We would describe the weather as changeable," she added. "We could see a mix of sunny spells and showers.
"There is around a 20% chance that we could see something a little bit hotter on Thursday.
"This could mean heating up towards 30C or the low 30s. That has the potential to trigger some rain.
"There is a wedge of really hot air that is going to blow over France. That air could waft over the south of England."
If that happens, temperatures in eastern and southern England could see temperatures of 33 or 34C.
"I would advise those going to Glastonbury to pack for all weather - bring your Pac a Mac and sun lotion," the spokeswoman said.
There was no rainfall during the first Glastonbury Festival in 1970, which was attended by 1,500 people.
Only seven other years of the festival have not seen any rain.
The hottest days were in 2010 and 1989, when temperatures reached 27.3C - leaving some revellers with heat stroke and exhaustion.
In 2005, the festival was delayed after rainfall left some areas of the site under 4ft of water.
This year, Glastonbury Festival will play host to Labour leader Jeremy Corbyn, who will introduce US rap duo Run The Jewels and appear at the LeftField tent for a talk.
Clive Lewis, MP for Norwich South, tweeted: "Chuffed to be speaking on Sat June 24 at #Glastonbury2017.Recharge your activism at the Leftfield tent with special gueststar @jeremycorbyn".
Extra security precautions will be taken at the festival in the wake of the terror attacks in London and Manchester.
Avon and Somerset Police have said there is "no intelligence" to suggest a specific threat to the festival.
Ticket-holders have been told to pack light, place luggage tags or ID on all their bags and expect searches from before entering.
"Like the rest of the UK, festival-goers should be alert but not alarmed," assistant chief constable Caroline Peters said.
Glastonbury Festival is expected to be the most shared live event of the year, with mobile network EE expecting 40 terabytes of data to be used.
The telecoms giant, the official technology and communications partner for the festival, will place a temporary 4G network across the site.
It is also providing free 4G wifi and phone charging on-site, including wireless charging for the first time.
"With social media continuing its rapid growth - including the recent addition of Instagram Stories, Facebook Live and Snapchat Stories - those on site now require more data for video than ever before," Mat Sears, EE's director of communications and sponsorship said.
Worthy Farm will host 10 information signs powered by urine, thanks to a new 40-person urinal situated near the Pyramid Stage.
The urine is converted into electricity thanks to technology developed by the University of the West of England.
A second "Pee Power" site at the festival will charge lighting and mobile phones.
Glastonbury Festival takes place from Wednesday June 21 to Sunday June 25.