On Memorial Day the flag is flown at half-staff in the forenoon (the time period between dawn and noon), then raised to the top of the staff. In the morning the flag should be raised briskly to the top of the flag pole, then slowly lowered to the mid-way point of the pole. At noon the flag should be raised to the top of pole. At the end of the day the flag should be lowered slowly and ceremoniously.
History of Memorial Day
Three years after the Civil War ended, on May 5, 1868, the head of an organization of Union veterans — the Grand Army of the Republic (GAR) — established Decoration Day as a time for the nation to decorate the graves of the war dead with flowers. Maj. Gen. John A. Logan declared that Decoration Day should be observed on May 30. It is believed that date was chosen because flowers would be in bloom all over the country.
The first large observance was held that year at Arlington National Cemetery, across the Potomac River from Washington, D.C.
By the end of the 19th century, Memorial Day ceremonies were being held on May 30 throughout the nation. State legislatures passed proclamations designating the day, and the Army and Navy adopted regulations for proper observance at their facilities.
It was not until after World War I, however, that the day was expanded to honor those who have died in all American wars. In 1971, Memorial Day was declared a national holiday by an act of Congress, though it is still often called Decoration Day. It was then also placed on the last Monday in May, as were some other federal holidays.US Department of Veteran Affairs