From sunrise to noon on Memorial Day the flag of the United States is flown at half-staff.

On the last Monday in May, Americans have, for over the last 142 years, commemorated those who have died in wars by flying flags half-staff until noon on Memorial Day. It’s been a practice that has been observed since an Army regulations book from 1906 issued instructions for the procedure.

Then, in 1924, Congress codified the tradition with a proclamation reading, “For the nation lives, and the flag is a symbol of illumination.” It was through this proclamation that the noon flag raising became the symbol of persistence of the nation in the face of loss.

But even then, there were no regulations for flying the flag at half-staff. This, as a result, led to many conflicting policies until March 1, 1954, when President Dwight Eisenhower issued a proclamation on the proper times that a flag should be raised to half-staff. These include periods of mourning proclaimed either by the president of the United States for national remembrance, or the governor of a state or territory for local remembrance.

However, while the origin of a half-raised flag is unclear, it has long since played a key role in honoring the dead. With the Civil War in America being a major turning point in commemorating and honoring those who died in battle, post-Civil War saw the conception of a day designated to remember those who gave their lives for their nation.

The question is, why is the flag raised half-staff only until noon, considering that with any other death honored by the state, the flags fly half-staff all day? This unique custom, which sees flags flown half-staff until noon and then raised to full height from noon to sundown is a means of honoring those who died in battle during the morning, while the rest of the day is meant to honor the living veterans – recognizing those who have sacrificed and those who are still with us.

One theory put forth is that flying the flag at half-staff is done to allow room for an invisible flag of death to fly above it.

The protocols for Memorial Day flags are that the flag should be flown at half-staff from sunrise until noon only, then raised to the top of the staff until sunset.

Other regulations for flying a flag half-mast include, flying the flag half-staff for 30 days at all federal buildings, grounds and naval vessels throughout the United States and its territories after the death of a president or former president. After the death of a vice-president, chief justice or retired chief justice of the United States Supreme Court, or the speaker of the House of Representatives, the flag is flown at half-staff for 10 days.

Others, such as an associate justice of the Supreme Court, a member of the Cabinet, a former vice president, the president pro tempore of the Senate, the majority leader of the Senate, the minority leader of the senate, the majority leader of the House of Representatives, or the minority leader of the House of Representatives, flags are to be displayed at half-staff from the day of death until interment.