Seattle year round commuter. For my current short commute: a rain cape (poncho).
- it's comfortable to wear both wet and dry
- easy on/easy off. Less fucking around trying to get geared up.
- I don't sweat through my clothes because it ventilates like crazy
So many more reasons, but good lord those 3 are reason enough. Putting on still-wet gear at the end of the day is nasty.
I also wear rain-legs. I wear wool socks and sneakers (1 less piece of wet gear to deal with). No gloves (cape deals with the rain and wind).