In just three short lines, the poem gives us a quiet winter picture: a swan standing or gliding in the snow, white against white. The speaker looks closely enough to notice the swan's nose, which is really its bill, and the comparison that follows is the heart of the poem. That nose is "as cold as news from the north."
It's an odd, clever simile. News from the north suggests something distant and chilly, maybe unwelcome, arriving from far away much as winter does. The comparison turns the cold from a plain physical fact into something with a hint of unease. The speaker doesn't say how they feel, but the tone seems watchful and hushed, a little wry, a little uneasy. Calling the bill a "nose" adds a touch of humor and tenderness, as if the swan were a small, shivering creature rather than a grand symbol.
The mood is still and pale, with the spare wording echoing the emptiness of snow. We're left with a sharp image and a faint sense that winter has brought more than weather.