In reply to Dr Avid:
Not so much that it gets nasty when wet (although it does) but it gets very fragile & holds start to break.
So avoid any holds that feel or appear in any way damp.
Having said that, most of Bowles & parts of Harrisons dry pretty quickly given a couple of good days.
It becomes even more important than ever to take a mat or carpet & clean your feet thoroughly whenever you step onto the rock as the ground tends to stay damp & you have to be prepared to leave a perticular route for another day if there are damp holds.