Dunno... I have a puffy but it's not strictly necessary. Even when it was -35 here in november (wtf that's still fall, fuck you) I was never cold wearing a coat and it didn't matter what coat - down, wool, even the cotton trench I'm wearing today was comfy in -10 and still fine in -20 as I couldn't feel the wind. Everything NOT covered by the coat or a scarf was freezing. Usually I'd be wearing a sweater but not always.