Glastonbury festival-goers look set to require a mix of "sun cream and wellie boots" according to the Met Office.
A heavy bout of rainfall is not expected to descend upon the event, as it did in 2005 when tents were washed away, but it is also unlikely to remain dry.
Temperatures also look to be fairly typical, with highs of 21 C to 22 C possible, but most likely to stay around the seasonal norm.
A spokesman for the Met Office said: "Thursday and Friday will be sunshine and showers. It's certainly not looking dry through the weekend."
This year's festival kicks off in earnest on Friday with headline sets from Arctic Monkeys, Bjork, Kasabian and Arcade Fire.
Saturday belongs to the godfathers of punk Iggy and the Stooges, while the main Pyramid Stage welcomes Las Vegas rockers The Killers.
Legendary band The Who will then close the main stage at the festival after sets from Kaiser Chiefs, the View and Manic Street Preachers.
Bad weather has been synonymous with the festival in the past with 2005 being particularly notable for its mud-slides and impromptu streams.
This year Glastonbury founder Michael Eavis has installed a series of pipes to take water away and added hard core below the soil to prevent it from turning into thick mud.
About 180,000 people will arrive in Glastonbury for the event, which is equivalent to the entire population of Norwich turning up at the small Somerset farm.