I commute because it is so much fun to ride a bike.
I ride in good weather.
But I also try if the forecast isn't that bad, if its just a chance if showers.
I don't go out in the rain - yet. Hopefully will get a fender-able bike soon and start venturing out in all weather Spring thru Fall.
I don't know how to do winter yet. But hope I can figure something out by next winter.