You can't layer down to less than nothing. Even if you are naked, most people will find being in 100 degrees of heat with 80% humidity extremely unpleasant. And

You can't layer down to less than nothing. Even if you are naked, most people will find being in 100 degrees of heat with 80% humidity extremely unpleasant. And it is the high humidity that is a major factor. 110 and 15% humidity is much more tolerable.