My commutes have ranged from less than a mile to my current 16.7 miles. The former was in the Bay Area, CA and I just wore my work clothes as I never broke a sweat. I had another similar commute in San Diego which was around 4 miles. Again, I just wore my work clothes. Weather rarely got too hot and inclement.
Now, I have a commute just shy of 17 miles one way in the DC area. It gets hot and humid here so having a locker room with showers at work (also a nice gym) helps.