Wind chill is a mostly stupid number that weather reports like to trot out so they have a amped up "wow it's really cold" factor. Yes, a number of factors p[lay into our subjective perceptions of temperature but you're probably not walking around in a bathing suit when it's below freezing with a howling wind.

But then this is also valid if the zero is at 21°C. There is also nothing special at 0°F, it’s just the colour scale that makes it look like that. And if we based the scale on human perception we’d have to define many other parameters besides wind and humidity, like body shape and metabolism rate. It’s more of an argument against basing a temperature scale on human perception (and then I agree completely, which is why I find the centigrade scale much better, except for serious business that demands kelvins).

Neither of those are as important as “when water freezes” (ice snow weather effects), boils, and having a nice 100d in between