Autumn here is really a stand-in for growing old. The poem opens with four short words about being alive, then four about time, and the second list turns darker: "ageing" slides into "dreading." Right away we sense that the man at the center is more afraid than peaceful.
The changing leaves carry the comparison. Reds, oranges and yellows make the village beautiful, but the poem keeps reminding us that this beauty is passing. Trees that were once full of green now drop frail leaves, just as the man has lost the energy of his youth. The line about the "boy of summer heat" standing in "autumn cold" sets his past and present side by side.
The mood is quiet, wistful and a little bleak. The chill wind and the shiver down his spine make the feeling physical, and the ending, "waiting for the inevitable truth," suggests he is thinking about death. The poem admires the season's colors, yet it never lets the sadness fade.