Four short lines, and a lot of quiet feeling packed into them. The speaker notices that summer hasn't entirely gone: its scent still lingers in wormwood, a bitter plant dried out by the sun. That detail matters. Even the memory of warmth here has a sharp, slightly harsh edge.
Then comes the boldest moment: "I am stronger than the sun." It could be read as pride, or as relief at having come through a hot, intense season. Judging by the final line, it may also be something gentler. The light in old clothing suggests warmth that has soaked into fabric and stayed, something carried around after the season itself is over. If so, the speaker's strength comes from holding onto that light rather than from beating it.
The mood is calm, reflective and a little defiant. Nothing is explained, so the poem leaves you with images: a smell, a plant, worn cloth glowing softly. The feeling is of summer fading, and of a person quietly outlasting it.