[osreb]

Myth #8: The flag should never be flown at night
Although it's customary to display the American flag from sunrise to sunset, the flag can be displayed 24 hours a day as long as it is illuminated through the night, according to the Flag Code.
"What we've taken that to mean is that it must have sufficient light that the average passerby can readily identify it as the flag of the United States,” Hendricks said.