An issue has recently come up in my neighborhood about flying the flag at night. I was wondering what is the historical significance of this rule. I know it was introduced in the "Flag Code of Conduct" in 1923. But I couldn't find any reasoning behind it. Can anyone shed more light on this subject for me?
It seems difficult to establish a formal link, but the US Army has long followed earlier military custom and lowered the flag in the evening and raised it again in the morning. The ceremony accompanying the flag-lowering is called Retreat (as in "retreat into the boundaries of the camp").
From WWW.ARMY.MIL "The official homepage of the United States Army" Retreat and Reveille: Pay your respects to the flag.
Retreat has always been at sunset. The music for retreat dates back to the Crusades and was first used by the French Army. The American Army has used this bugle call since the Revolutionary War. Retreat's original purpose was to notify sentries to start challenging until sunrise, and to tell Soldiers to go to retire to their quarters for the day, according to the manual.
The US Navy similarly lowers its flags in the evening at Evening Colors, in a ceremony that was formalised in the UK in 1790. This seems to have always been about the flag. EDIT: Though of course the lowering of the flag signals the end of the normal working day in the Navy too.
According to the US Flag Code, the flag may be displayed on a night with fair weather if properly illuminated.