I guess I'm thinking it's all about insulation. And the amounts needed stay warm or cool.If a Stormtrooper is hanging out in deep space nowhere near a star, the outside temperature is about 3 Kelvin. This can go up to almost 400 Kelvin (about 250°F/120°C) in direct sunlight in the vicinity of Earth, hotter closer to a sun like ours or near a more energetic star. The heating and cooling systems of Stormtrooper armor have to be able to regulate that, and cope with tenuous up to probably a couple times standard atmospheric pressure. The coldest temperature ever recorded on Earth was at Vostok Station in Antarctica, being -89.4°C -- or 183.75 Kelvin. Comfortably in the middle of the established range Stormtrooper armor would have to function within in space. When they were filming in Norway in 1979, it was one of the nastiest winter storms on record, and a positively balmy 239 Kelvin by comparison.
I've seen the argument that cold in snow is different from cold in vacuum. This is true. Vacuum is worse. Space is about the most caustic environment known for many materials. Things get brittle and crack that never do on Earth. This is why I can see standard Stormtrooper armor being used in both icy and sandy conditions -- it's already designed to take worse. The exception I allow for Sandtroopers is "hardening" to keep sand out. As anyone who's ever gone hiking or camping in the desert knows -- let alone spent some time in the desert for military purposes -- sand gets places you never knew existed. While Stormtrooper armor works in the desert, I'm willing to bet those 'troopers spent weeks finding sand in places it should not have been physically possible to get.
If you look at, for instance, the Gemini suits. Or the insulating layers on the LM. It's very thin layers. That's all that's needed. Where's there's no atmosphere. Set the LM in -30f temperatures, with the wind blowing, even with strong heater inside, it's going to be cold in there. In northern climates, houses are built with 6 inches of insulation in the walls. I can't uses a mylar and kapton blanket to insulate a house. I can however insulate a spacecraft, with my layered mylar and kapton blanket. Because that's all I need a thin reflective layer. Because there no atmosphere, the heat loss is very slow. And in the same way, the heat transference to a person or spacecraft is slight, when the reflective material is spaced away.
The Stormtroopers armor would work great at keeping the trooper cool, being white. And we can imagine that it's insulated away from the black bodysuit to slow any transference. Though the black areas would heat up.
Of course we're messing with the fuzzy divide between science and science fiction.
I mean realistically Stormtrooper should probably do it all. But it looks sooo cool to have all these different types. And Snowtroopers just look amazing.All of the stuff Snowtrooper armor is described as having makes perfect sense and is totally fitting... for an Imperial infantryman or a Stormtrooper. We already know Stormtrooper armor can take worse. And I've seen enough movies of what wind-driven snow can do in the Winter in Antarctica. It can be almost as bad as blowing sand in hot deserts for getting in where it isn't wanted. But unlike sand, it melts. Especially given the clear conditions on Hoth when the Empire attacked, I can't see Stormtrooper armor being fussed by the weather there.