It’s possible to dress smartly to be warm. It’s amazing how many people bundle up in a way that makes them colder, then complain that it’s really cold outside. I walk around in short shirt sleeves in temperatures a few degrees above freezing, and I’m comfortable and in no danger. I have a sweater in my backpack, just in case. Carrying it makes it easier not to wear it, because I don’t fear turning into an ice cube, since I know I can do something about it long before then. There’s something of a science, and an art, to staying warm.
This isn’t about being fashionable or presenting a business appearance. But it doesn’t require looking like the Michelin Man. And dressing to be warm can be very inexpensive.
In short: Dress lightly. You’ll be fine.
This discussion is mainly relevant to the temperate zones of the world, with much of the information specific to the United States.
About me: I’m not a doctor or a professionally trained allied health professional. I went winter backpacking solo long ago and, in the year or two before that, taught myself the skills I’d need to stay warm and healthy. On one Adirondacks trip, a farmer told me 14 inches of snow had fallen the night before and, even so, I didn’t wear the wool pants or hang the tent liner. I was warm and relaxed, I had fun, and I got home in good shape.