I'm still new to commuting. Started this summer and have done about 4 rides or so. I've been caught in the rain twice, but it was light both times.

1. My cycling sunglasses haven't fogged up or anything in the rain. When the weather is hot and humid outside, my regular glasses will sometimes fog up when I go into an air conditioned building. My cycling sunglasses have not done this.

2. I didn't have slipping problems with the grips, which are covered in some kind of faux-leather tape.

3. My bike came with wide (1.75 ") "all weather" tires for handling potholes, gravel, and sand as well as road, so they're fine on wet pavement. I suspect I'd have to be more careful if the bike had skinny road bike tires. In any case, I try to ride slower if it's raining, and try not to put myself in any situation where i'd have to brake suddenly.

I'm comfortable commuting by bike when the forecast calls for rain. What I avoid is thunderstorms - nobody seems to have any good answers for riding when lightning is in the air, other than to seek out a bridge of some sort and wait out the lightning; or just don't ride at all (drive, take bus, take subway, etc.).