Labor Day is the U.S. holiday traditionally associated with the phrase “no white after Labor Day.”
The fashion rule was never a federal regulation, and many Americans no longer follow it. Its origins are linked to late-nineteenth- and early-twentieth-century social customs, when clothing choices helped distinguish wealthy urban groups and seasonal wardrobes. White garments were associated with summer leisure and resort life, while darker clothing suited autumn and winter city life.
Labor Day became a convenient seasonal boundary because it falls near the end of summer vacation schedules. The holiday weekend therefore acquired cultural meanings beyond its official purpose of honoring workers.
The rule is not a universal historical principle: white clothing has long been worn year-round in many places and climates. Modern fashion treats it as an old convention rather than a binding standard.