You can’t see it, but a very thin layer of protective air — known as your microclimate —surrounds you wherever you go. We are most comfortable with a microclimate of around 90°F and a relative humidity of less than 30 percent. Even the slightest change to these levels will quickly cause you to feel uncomfortable.
But what’s good for one part of your body isn’t always good for another. In cold weather, for example, our arms and legs can be up to 45° colder than the rest of our body without causing any discomfort. And if your head is uncovered, a warm coat won’t be able to keep you comfortable because you lose more heat through your unprotected head than your entire body can produce.