Is the Wind Chill Factor an accurate representation of outdoor temperature?

The Wind Chill Factor attempts to measure how cold it “feels” outside, not just the absolute temperature. The first formulas to calculate this factor were developed in the 1960s and 1970s but were not standardized in North America until very recently (2001). The UK follows the North-American methodology but a number of other countries utilize their own formulas and scales.

The concept behind the Wind Chill Factor is scientifically valid. Humans (and most animals) constantly generate heat, creating a thin boundary of warmed air around your body that acts as an insulating layer. Wind, at sufficient speed, carries this heated air away, thus making your skin feel colder than it would in the absence of the wind.

There are a number of problems with the Wind Chill Factor. Firstly, it assumes that all of your skin is exposed to the air, which is most likely not the case in the chilly temperatures at which the WCF becomes applicable (clothes trap heat and block the wind). Secondly, there is a common misconception that the temperature is literally lowered because of the added wind – in fact, your skin cannot become colder than the ambient temperature no matter how strongly the wind is blowing – it just feels colder. Thirdly, another misconception is that the WCF applies to inanimate objects (e.g., water will freeze faster at a lower WCF). This is not true because the entire concept of the WCF relates to the heat generated by living, warm-blooded creatures. Finally, the WCF has been criticized because it attempts to quantify a feeling or perception which is in fact highly subjective among different individuals. For example, women generally feel the cold more strongly than men due to lower muscle mass and higher body fat (fat doesn’t insulate from the chilly air but rather blocks body heat from reaching the skin).