Even when it is cold, I try to wear as little as possible when walking to avoid sweating.
I walked to my stand on 12/9/07 in a single, long sleeved UA shirt. It was 14 degrees, out. I dressed when I got to my stand site.
It's a tough call.....deciding what you CAN and CAN'T getaway with wearing without sweating......taking into account your hike and how much gear you're hauling around (and what your physical condition is). I struggle with this, all season.