Flag at half-staff

Memorial Day is a solemn day of remembrance for honoring and mourning military servicemembers who have died while serving in the United States Armed Forces. This federal holiday is annually observed on the last Monday of May. This year Memorial Day is observed on Monday, May 25.

In accordance with the U.S. Flag Code [U.S.C. Title 4, Chapter 1, Section 7(m)], on Memorial Day the United States flag is to be displayed at half-staff from sunrise until noon only, then raised briskly to the top of the staff until sunset.

The White House proclamation can be found here