This depends on the person. Looking at this past febuary it had a min of -4F. We had similar in AR back in 21 and I was outside in a tshirt or if more than 10

This depends on the person. Looking at this past febuary it had a min of -4F. We had similar in AR back in 21 and I was outside in a tshirt or if more than 10 minutes the thinnest windbreaker ever. (Single layer of plastic and compresses to a baseball size or so.) I might go to a hoody at -20 but not sure even then.