At this time, we don't know what Skyrim will look like, since we've yet to see any in-game screenshots. and even once we do see them, one screenshot is probably not indicative of the entire world, but there are two things I feel safe in saying. We WILL see snow in Skyrim, and the game will not ALL be snow. Obviously, Skyrim must have some snow, it's the furthest north of all provinces, and it seems obvious that in Tamriel, the further north you go, the colder it gets. Plus, when one thinks of Nords and Skyrim, one cannot imagine a place without snow. But still, as some of pointed out, in lore, Skyrim is not supposed to be only that, and while Bethesda has proven that they are willing to change how certain provinces are portrayed in lore if they do please, I think they understand that a game with only snow and ice will get boring, especially considering how Oblivion has been criticized for a lack of variety in landscape, and yet that game is still more varied than some seem to expect Skyrim to be. In conclusion, no, I do not think we will see only snow in Skyrim, more than that, I won't say until we have more information.
Bethesda has been known to stray far from previous perceptions of certain areas. Cyrodiil was supposed to be a huge jungle.
While this is true, the terrain of Cyrodiil at least seemed plausible to me if one ignores previous lore and only looks at the geographical location of the land. This is not to say I approved of the decision to turn Cyrodiil into what we got in Oblivion, because I don't, and I feel that Bethesda's "explanation" for the change feels like a half-hearted handwave. But putting aside personal preferences and previous conceptions of what Cyrodiil might look like, based on old lore, Cyrodiil seems plausible enough. On the other hand, while I could certainly see Bethesda defying players' expectations of Skyrim to an extent, I can't see it having tropical jungles or anything.