Get yourself some good wet weather gear and you won't even notice it's raining. I have a waterproof lighweight rain jacket which keeps out all the rain for the upper half. For the lower half, I have purchased some 3/4 length wet weather shorts. these things are great, they are 100% waterproof and can wear them over my shorts, or if I'm wearing pants I just roll up the legs and problem solved. If I'm commuting, I'll always take a spare change of clothes in my panniers anyway, but normally I'm still dry when I get to work.
Riding in the rain is good fun, embrace it !