Continuing the theme...it's surprising to me how little I have to wear to be comfortable while riding. Yesterday it was ~26F as I rode in. I was OK just wearing 2 layers of UnderArmour (the bottom layer is just the regular thin stretchy stuff; the 2nd layer is their "Winter gear", 2 layers thick but still not much). On my legs I had brushed-fleece tights (medium weight, not the heavy stuff) and cycling shorts over them.

Walking into the building I was surrounded by people leaving their cars wearing heavy winter jackets. I'm ALWAYS cold (I have no body fat for insulation) so the fact that I can be comfortable wearing that little speaks volumes.