I actually enjoy riding in the rain, but if there's lightning in the forcast (which doesn't happen very often), count me out. I don't ride if there's a lot of snow/ice on the roads. As long as the roads are clear and taken care of well, I usually ride. I'm not a huge fan of heavier (20+mph) winds, but I'll still ride as long as I have enough time to make it in.
I also plan one day a week to drive to take care of errands and bigger shopping trips. For the smaller shopping trips I'll ride and fill my panniers up.