Memorial Day is a holiday today in Massachusetts, and that changes the rhythm of the state in ways people will notice from the mailbox to the train platform. The post office is closed, all RMV offices and serve centers are shut, and MBTA subway and bus service is running on a Sunday schedule, while the Commuter Rail is operating on a weekend schedule.

For anyone trying to get errands done, most stores are open for normal hours, including Market Basket and Big Y. Pharmacies inside supermarkets may have limited hours, and liquor stores in Massachusetts cannot sell alcohol until after noon. The Hingham/Hull/Logan to Boston ferry is on a Sunday schedule, while the East Boston, Charlestown, Lynn, Winthrop and Quincy ferries are on a weekend schedule.

Memorial Day is a federal holiday, and in Massachusetts it is also a holiday for public schools and libraries, which are generally closed. It is observed as a day of remembrance for the men and women who died while serving in the country's armed forces, and that meaning shapes the day even as many stores stay open and transit keeps moving.

In Boston, 37,000 American flags have been planted on Boston Common as part of the city’s Memorial Day displays, a visual marker of the scale of the remembrance. Parades and ceremonies are also taking place in towns across Massachusetts, giving the holiday a public face even for people who spend much of the day on ordinary errands.

The pattern is straightforward: essential government services are scaled back, retail mostly keeps going and transit shifts to holiday service. For Massachusetts residents, the biggest thing to know is simple — if the trip involves the post office, the RMV or a morning liquor-store run, Memorial Day changes the rules today.