A meta-analysis of the effect of body and air movement on the insulation provided by workwear and cold-weather clothing [1.22 clo (0.189 m2 degrees C W(-1)) < I(T)<4.14 clo (0.642 m2 degrees C W(-1))] using data from different sources was performed. For the effect of walking, datasets could be merged and a single prediction equation produced (r2=0.91). For the effect of wind, and interaction of movement and wind, separate equations were required for regular workwear (r2 = 0.93) and cold-weather clothing (r2 = 0.97). Differences were mainly due to the different amounts of nude surface area. An interaction between wind and walking effects was present (the size of the combined effects is less than the sum of the separate effects), and for cold-weather clothing an effect of clothing air permeability (p) was present (high p --> bigger effect). The resulting prediction equations will be proposed for inclusion in European and ISO standards on protective clothing to assist the user in determining the real-life clothing insulation value.