I shower before leaving for work, then under-dress slightly on my way to work most of the time -- if I'm pushing hard, I'm warm but not too sweaty; if I have to stop for long, I'll get cold unless I put on a jacket. (For example, this week it's been in the upper 30s in the morning, so I've been wearing light tights, bib shorts, and a sleeveless jersey. Plenty warm as long as I'm riding hard.) The last half-mile to work I slow down a bit and unzip my jersey or jacket depending on the weather, so I'm mostly cooled off when I get to the office.

I ride three miles to the train station, sit on the train for half an hour, then ride a bit over six miles to work up and down the hills of Seattle -- not a commute I want to do in slacks and a dress shirt, especially when it's raining. Slacks and an undershirt go in my pannier, dress shirts and shoes live at the office -- I use the dry cleaner across the street, so my shirts never go home, just off to the cleaners at lunch once in a while.

No shower or lockers at work, I change in the men's room. In the hottest parts of the summer I do a quick sponge bath, otherwise, cooling down before arriving is good enough.