There are 5 official days to fly a Flag at Half Staff.
Peace Officers Memorial Day, May 15th
Memorial Day, last Monday in May (Flag raised to full staff at noon)
Korean War Veterans Day, July 27th
Patriot Day, September 11th
Pearl Harbor Remembrance Day, December 7th
Aside from these days, Only the president of the United States or the governor of the state may order the flag to be at half-staff to honor the death of a national or state figure.
Only the President and state Governors can decide when and how long the flag should be flown at half-staff.
Thirty days after the death of a president or former president
Ten days after the death of a vice president, the chief of justice or a retired chief of justice or the speaker of the house of representatives.
Until the burial of an associate justice of the Supreme Court, secretary of a military department, a former vice president, or the governor of a state, territory, or possession.
On the day of and the day after the death of a member of Congress.
On Memorial Day, the day set aside to honor all the people who have died while serving theUnited States & originally called Decoration Day, the flag is flown at half-Staff until noon, then raised to full staff until sundown.