Half-staff, half-day

This year's Memorial Day Presidential Proclamation states, "I...request the Governors of the United States and its Territories, and the appropriate officials of all units of government, to direct that the flag be flown at half-staff until noon on this Memorial Day on all buildings, grounds, and naval vessels throughout the United States and in all areas under its jurisdiction and control."

The U.S. flag is flown at half-staff only for the first half of the day, and then it is raised to full height from noon to sundown. Why only until noon? This custom honors the war dead for the morning and living veterans for the rest of the day (Live Science).