When I rode to work today it was 26 degrees outside with a slight cross wind. The calculated windchill was approximately 1 degree, give or take. At that temperature frostbite can begin setting in within 30 minutes.
The only part of my body that felt cold was my eyebrows. Yes, my eyebrows. My HJC modular helmet lets a sliver of air come in from the top of my face shield and it hits me right above my eyes. My Aerostich Darien jacket, Fieldsheer pants, and Alpinestar boots did a great job keeping their relative body parts comfortably warm, as did my generic Gore-tex ski gloves for my hands.