Convection heat loss increases as wind speed increases.
Wind chill is a function of air temperature and wind speed at 5 feet above the ground. A wind chill chart is available at http://www.wrh.noaa.gov/lkn/windchill.php.
If you must be or choose to be outdoors during bitter cold temperatures do these things:
1. Dress in layers
2. Minimize any exposed skin
3. Use clothing, natural features, or structures to minimize wind exposure
4. Maintain a warm core by staying well fed and well hydrated
5. Watch for signs of cold challenge and mild hypothermia and intervene early
6. Watch for signs of superficial frostbite in yourself and your companions and intervene early
Greg Friese, MS, NREMT-P, WEMT