A person walks through the rain and feels, for once, not gloomy but free. The speaker doesn't hurry or shelter from the weather. Instead there is a small smile, wind in their hair, and the sense that something heavy has just come off their heart. The rain here isn't a sad backdrop; it feels more like a cleansing, something that makes the moment fresh.
The last two lines explain the change: "starting today, / I'm walking my own way." The speaker seems to have made a decision to live on their own terms, perhaps after a stretch of doubt or pressure, though the poem doesn't say what it was. The literal walk and the figurative one become the same thing.
The mood is quiet and hopeful rather than loud or triumphant. Short lines and simple images keep it gentle, like a private moment of relief. The smile is "small," which makes the happiness feel real and understated.