Three short couplets sketch a single winter evening: snow-covered hills, a soft sky, and the last of the daylight fading. The poem is quiet and observant. The speaker doesn't tell a story or state a strong emotion, but simply watches the landscape settle into night.
The second couplet is where things shift. Stillness takes over from the busy life of the day, and the only sound left is the wind, which the speaker pictures as a playful fife, a small flute-like instrument. That image keeps the silence from feeling bleak, since the wind seems almost cheerful. The dash at the end of that couplet carries the sentence into the final lines, where the moon travels across the sky while everything waits for the morning star.
The mood is calm, patient, and gently hopeful. Night here isn't frightening; it's a pause, and the poem ends looking ahead to morning.