Autumn's arrival is gradual, but the cold comes abruptly

"Autumn's touch comes slowly, but the chill is sudden. Unaware that summer has passed until a rain makes one realize the depth of autumn. Some emotions are self-evident."

This translation captures the essence of the original text, conveying the gradual onset of autumn, the suddenness of the cold, the realization of the season's change with rain, and the unspoken emotions.