In reply to Expedition Hot Rock:
i can only back up how wet the ground is - i've spent about 5 days out of the last two weeks in the Berwyns, Arenigs and Craig Goch area, and it is wet.
wet wet wet.
unless i fancied sleeping on rocks, i reckon there were less than a dozen bivi pitches that were dry enough to avoid drowning between the three of them.