YR is Norweigan and is the best forecaster if you're going to a festival in Scandinavia:
"The calculation of the weather’s development is made in a 3D grid. The squares in this grid are 2.5 kilometers wide for the Scandinavian region and around 9 kilometers for the rest of the world."
Weather forecasts on Yr - how are they made? – Yr help and information
Wednesday - Old Time Sailors, maybe a dance class in Glasto Lation
Thursday - Thrill Collins, Guise, Frank Turner, Doreen Doreen, Freddie and the Freeloaders, Wheel of Four Tunes
Friday - Squeeze, Olivia Dean, Radical Round Up, Sugababes, Frank Turner, PJ Harvey/Seb Lowe, Haircut 100, Jungle, Cirque du Bulgar or Rimski's Yard
Saturday - Elles Bailey, Kingfishr, Last Dinner Party or Albert Lee, Manfreds, Black Pumas or Yard Act, the Streets, Coldplay, Berthrands Toys
Sunday - The Zutons, Seasick Steve, ??, Shania Twain, Jordan Rakei, Lottery Winners, Burna Boy, The National or Gipsy Kings, poss Doreen Doreen, Freddie and the Freeloaders if not another night.
Maybe. But who knows?