Here is a short list of annual observances emphasized by the National War Museum Project. (Note: The list does not include at present anniversaries of battles, recognition of end-of-war days, and other days in military history).
Four Chaplains Day, February 3rd each year
National Medal of Honor Day, every March 25
National Vietnam War Veterans Day, every March 29
Armed Forces Day, celebrated on the third Saturday in May
Military Spouse Appreciation Day, celebrated on the Friday before Mother’s Day each May
Memorial Day, celebrated on the last Monday in May
National History Day, recognized in June
Flag Day, every June 14
PTSD Awareness Day, every June 27
Independence Day, every July 4
Purple Heart Day, every August 7
Constitution Day, every September 17
National POW/MIA Recognition Day, celebrated on the third Friday in September
Veterans Day, every November 11
Gold Star Mothers Day, celebrated on the last Sunday in September