With a heavy heart, nerf winter coats

[Grayshift]

Seems reasonable. Turns out suits in general have some hidden bonuses in addition to their listed protection value.

Try comparing the cold resistance value between being naked and wearing a suit to the value the suit tooltip displays.

(Note that holding an item in hand counts as having it in your equipped items. This is dumb but endemic enough that I'm not going to fix it here for fear of breaking other things right now.)