White is the color named in the traditional U.S. fashion rule about clothing after Labor Day.
The saying “you can’t wear white after Labor Day” became a shorthand for an old seasonal clothing convention. It was never a federal rule or a universal social law; rather, it reflected upper-class fashion customs in the United States during the late nineteenth and early twentieth centuries.
White clothing was associated with summer, resorts, and escaping hot city environments. After the September holiday, darker colors and heavier fabrics were traditionally favored for autumn and winter wardrobes.
Modern fashion has largely abandoned the restriction, and many people wear white throughout the year. The expression remains culturally recognizable because Labor Day is often treated as the unofficial boundary between summer and autumn in the United States.