The purpose of this study was 1) to develop a large, representative database of static and dynamic insulation values for different types of clothing designed for use in cold environments, 2) to determine the change in insulation due to walking, and 3) to develop regression equations for predicting static insulation and dynamic insulation from selected clothing variables. Thirty clothing ensembles including ski wear, hunting gear, work clothing, and “everyday” outdoor clothing for men and women were studied. The insulation values for the ensembles were measured according to ASTM Test Method for Measuring the Thermal Insulation of Clothing using a Heated Manikin (F 1291) with a thermal manikin standing and walking in a cold environmental chamber. In addition, the number of garment layers were counted and their thicknesses were measured on the torso, arm, thigh, and calf. Results indicated that the static intrinsic clothing insulation values ranged from 1.10 to 3.67 clo. The dynamic intrinsic insulation values were lower due to an increase in convective heat transfer within the clothing systems during movement; they ranged from 0.53 to 3.21 clo. The decrease in insulation due to walking varied from 12 to 51%. The number and thickness of garment layers on the arms and calves were good predictors of static insulation (R2 = 0.87) and dynamic insulation (R2 = 0.90). The equation for predicting dynamic insulation from static insulation accounted for 95% of the variance in dynamic insulation values. The insulation data and regression equations developed in this study can be used to estimate the insulation provided by cold weather protective clothing.