The only tight layer is the first.

My winter set up is:

First layer: tight top + bottom wool long johns (in sure there is a proper term for em, but it’s what we called em)

Second layer: loose wool onesie I got from Roots.

Third layer: loose sweat pants + hoodless sweater

Fourth layer: loose insulated work pants + work hoodie

Fifth layer: snow pants and jacket

This gets me through winter in Winnipeg and rarely do I get cold.

And cause 87% of the planets population resides above the equator.

The answer is quite simple