When I was a cadet we used to wear winter dress (the dark blue long sleeve shirts with ribbons, ties, nametags and collar devices) during the winter and trops (which used to be called tropical blue long) in the spring, fall and summer.
Eventually, as good little cadets we started "working blue Wednesdays". Working blues are those ugly, but comfy uniforms that looks like gas station attendant uniforms. The working blue trou, combined with the trops shirt (with collar devices instead of shoulder boards, and no ribbons) and boots instead of leathers, were called "Undress".
Anyway, "winter dress challenge" was making it through the entire winter wearing only one winter dress shirt.
Winter dress was made out of some material that allowed you to just scrape food right off of it, but if you ironed it, the material got really shiny (because you semi-melted it).