Her smile is a ray of sunshine on a cloudy day.
Meaning: Her smile makes me happy, even when I'm feeling down.
Choice of Words: Ray is a line of light or heat from the sun or another source. Sunshine is the light and heat from the sun. Cloudy means covered with clouds. Together, they create a metaphor where her smile brings light and happiness into my life, even when things are difficult.
Alternative Expressions
Related Expressions