Memorial Day weekend is commonly regarded as the unofficial start of summer in the United States.
The holiday falls on the last Monday in May, near the end of spring. Its long weekend is associated with warmer weather, outdoor gatherings, travel, swimming pools, barbecues, and the opening of many seasonal attractions.
This seasonal description is cultural rather than astronomical. Astronomical summer begins at the June solstice, while meteorological summer begins on June 1. Memorial Day therefore serves as an informal calendar marker rather than the scientific beginning of the season.
Memorial Day’s primary purpose remains remembrance of U.S. military personnel who died in service. The summer association is a later social custom and should not be confused with the holiday’s historical meaning.