Heavy rain and thunderstorms are due to hit most of the country on Saturday as thousands of music fans head to Scotland’s biggest festival.
TRNSMT music festival began at Glasgow Green on Friday, with 50,000 fans expected to attend each day.
The Met Office has issued a yellow weather alert across the UK and warned of increased health risks.
Glasgow is expecting warm spells alongside high winds and thundery downpours throughout the day.
The warning comes after Tiree Music Festival was cancelled on Thursday, just a day before it was due to begin, because of gale force winds.
Islanders rallied to accommodate festival-goers on the Hebridean island and about 100 passengers had to spend a night in Oban ferry terminal.
Glasgow is covered by the yellow weather warning between 09:00 and 23:59 on Saturday.
The Met Office has warned of potential flooding and the risk of power cuts and damage to buildings.
Public transport may also be delayed or cancelled.
The weather is due to become calmer on the final day of the festival on Sunday.
TRNSMT began on Friday with Pulp, Sam Fender and The 1975 headlining over the weekend.
The Britpop band topped the bill on the opening night, following acts including George Ezra, Niall Horan, Paul Heaton and The View.
Horan told crowds during his set he felt like he was at a “homecoming gig” and that he had never seen a home nation “more up for it”.
“This is something pretty special,” he said. “One of the best gigs you could ever do is in this city.”
He also gave a shout out to close friend Lewis Capaldi, who recently announced he was taking a step back from touring after struggling to finish his Glastonbury set.
Friday also marked Pulp’s first show in Scotland since they played the main stage at T in the Park in 2011.
Sam Fender returns to TRNSMT for his fourth consecutive year with the headline slot on Saturday after Kasabian, Aitch, and Mimi Webb.
Headliners The 1975 will bring the festival to a close on Sunday night.
ScotRail has put on extra train services to cope with demand, including more late-night trains running to Inverclyde, Ayr, Edinburgh, and East Kilbride.