U.S. Labor Day traditionally marks the unofficial end of summer.
The holiday occurs on the first Monday of September, near the transition from the warm-weather vacation season to the school and autumn calendar. Many Americans use the long weekend for final summer trips, outdoor gatherings, and community events.
“Unofficial” is important: Labor Day does not legally end the astronomical or meteorological summer. The phrase describes a social convention that developed around school schedules, seasonal travel, and the return of regular work and cultural activities.
The holiday’s original purpose was to honor workers and the labor movement, not to mark a season. Over time, commercial and social traditions added the summer-ending association. The date also became linked to fashion conventions, football season, and the beginning of fall cultural programming, although those customs vary by region.