A speaker walks out on an October night and finds the whole world transformed. The poem opens and closes with the same declaration of love for these "grand" nights, which gives it the feel of a small, heartfelt frame around a single walk.
Inside that frame, the details are simple and physical: a crisp wind pushing past a jacket, a hush over everything, and a swollen moon peeking out from drifting clouds. The clouds blur the speaker's view, so they have to walk slowly and feel their way along. Instead of frustrating them, this seems to add to the wonder. The moon is described as "coyly" peeking, as if it's playing a game.
The key moment comes in the question near the end: "When have I ever felt so elemental, so alive?" The speaker feels stripped down to something basic and fully awake. The mood is quiet, dreamy and a little private, a celebration of how a cold, dim night can make a person feel vividly present.