In reply to Paul Hy: as said above, if the road is dry then crag is usually dry. Many people say that Striptease stays dry even in heavy rain, I've climbed it in the rain. Not much fun. Merlin drys pretty quick.
If its raining hard but still wan to climb then go and do The Hylldrem Girdle on Carreg Hylldrem. HVS 5a and you are traversing under a roof for the first 3 pitches. Do able in the pouring rain.