My American husband will be in attendance in 2020. He has a theory that all British people lie about the weather to keep tourists away, because each time he's visited it's been blazing hot. So, I suspect it will be blazing hot.
But then on the flipside, all the Glastonburys I've been to have been cold and wet.
But on the contrary, we're going to be carrying in a LOT of wet weather gear, so sods law says we won't need any of it.
Then again, every festival my husband has been to with me has been cooler than normal.
So take your pick.