10 1/2 miles morning to work, 15 (long way) going home. The last couple months in central IL (and most of the US) have been a scorcher. I ride to train as well, since I do race road races, criteriums, and time trials. My work has a shower & full size lockers.

^^^ I commute in a full kit, with clipless pedals.

If I need to go pick up milk at the grocery store, I just go with whatever I'm wearing. I can ride easy enough to not even break a sweat in 90+ heat, so shorts and a tshirt work fine when I'm tooling down the street to the store. Every ride is different, I use my bike for different reasons, not just to commute and run errands.

I could care less what others wear.