In reply to C133dnb:
Varies massively, both in terms of weather (mountain crags can be soaked, coastal venues baking hot) and how quickly they dry (aspect/ drainage/ wind direction etc.) the big difference is that most of the rock can’t really be damaged by climbing it in the damp, so that’s good
Potential good shouts for rainy days:
Tanygrisiau boulders (south facing)
carreg hylldrem (almost rainproof)
garreg ogof by trawsfynydd (can be in the rain shadow of the mountains)
RAC (dodge the showers and it can dry very quickly)
porth ysgo (v dodgy/ limited with one mat though)