We hate to break it to you, but "The Snow Man" has, well, nothing to do with winter. Sure, it's chock full of wintry imagery. But winter here is more just a convenient way to talk about the wonders of the mind.
Title: Admit it: you were expecting a Christmassy poem complete with gingerbread men. Sorry to disappoint, but that's not what Stevens is after here.
Line 1: Taken on its own, this line is more than a little alarming. "One must have a mind of winter"? Well, what if I don't wanna? Thanks to Steven's fondness for enjambment, we have to wait for the rest of this sentence.
Lines 2-6: Check out all these delightful descriptions. Winter is taking all kinds of shape in these lines, with their lush adjectives and beautiful images. That's precisely the point. Stevens is showing us how imagination can work its magic on a scene, which, we'll find out later, is really just a bare landscape.
Lines 10-12: Here we find that the winter, without the imagination projecting all kinds of things onto it, is not much more than a "bare place." Winter only becomes winter when we make it so. But if we have a mind of winter, it's just, well… winter, minus all the things we associate with it.