Riding in the rain is not much different. Some folks actually like it. Here's some tips for it:

- Use a decent rain jacket. Mine acts like two layers. So I can omit a layer in the colder months.
- Wrap work clothes in a plastic bag (if you carry them). My backpack can leak at times so this helps.
- Try a big shower cap. You can use it on your helmet and then the seat if you lock your bike outside.
- If no showercap, then bring an extra plastic bag to cover the saddle. Its a little ghetto, but it works...
- Try using fenders if your bike can fit them.
- Try a traditional cycling cap with a visor under your helmet. The visor will help keep the water out of your eyes.
- Try a shoe cover that's stretchy and more water resistant. If nothing else, it will keep the road grime off of your shoes.
- Use bright front and tail lights. You will need them more in the rain (or overcast days).
- Stay on top of your drivetrain. Check chain stretch with metal ruler, wipe chain after every ride. Lube chain when it looks dry or makes noise. No special lube needed. I use air tool oil.
- Leave cycling glasses in backpack or at home. It will be a pain to clean them in the rain. Try contact lenses if you need glasses to see.
- Many tires that work well in dry should be ok in rain. Pick your favorite.
- Try less air in the tires. I usually have 5-10 psi less.
- Use decent brake shoes. I like the Kool Stop Salmon or Swisstop black pads so far. Give yourself more time to stop at lights, etc.
- Like others above, I avoid metal objects on the road (grates, manholes, bumpy sidewalk pads, curb cover, etc) and some paint. Got a spectacular blowout once from a metal curb cover (from rear wheel sliding across it and then catching the concrete). Also ruined the tire.