I think my wardrobe is always winter-ready! Today I am wearing straight dark jeans, mid-weight grey sweater with camisole under, suede booties. Grey scarf and navy coat for outside.
We are going right after work to a friend's boat for the annual winter sail-past. The boats are all lit up in Christmas lights, I have a hot crab dip made (boat has oven to heat it), and some ciders packed. Should be a fun evening.
I have a very casual job where jeans or cords are fine. So jeans, sweater, vest (you call it a gillet?) and scarf are my basic wardrobe. I do my best to keep it coordinated and smart.