Do we have no proper 'pagan morris' sides or 'weather witches' for Gaia's sake?
No? Oh well, at the first sign of clouds simply grab the nearest folkie with a Unicorn tee shirt and stick them onto a bonfire.
Old folk tradition (well not quite).
It might not banish the rain clouds as such, but a bloody great bonfire is definitely warming when roughing it at a folk festival.

Anyway Mr. Bridge, my web page says different to yours (sunny all week) so I think I'll simply keep looking at that and expecting the best..