Meaning of figurative language: The metaphor presents an implicit comparison between the girl's mental state and her unhappiness with a cloudy, melancholy and dull day.
Effect on tone and mood: The metaphor promotes a melancholy tone and a sad mood, as it shows how racism and intolerance can end the happiness of a child who is being prevented from having fun just by the color of her skin.
Effect on audience: This allows the audience to feel uncomfortable with racism, because it realizes how depressing it is for those who are attacked by it.