The poem begins like a caption beneath a picture: a view of a lake, a town at the foot of mountains. Almost at once we learn we may not be looking at a real place at all, but at a "brush drawing in grey wash and graphite." The scene is already a representation, and the poem keeps moving further from the thing itself.
The comparisons pile up. The fog shifts with the heat "like the copy of a watercolour," and the original is "unidentified," so we can't check what is being copied. Then come two softer images: morning breath in winter, and "the resemblance of a simile," a comparison that compares itself to something else. The speaker seems less moved than curious, and perhaps a little wistful about how hard it is to catch a place in words or paint. The mood is hazy, quiet and slightly detached, like fog. The single word "Como" at the end feels like a name left hanging, as if the place has been approached but never quite reached.