WHEN TO DISPLAY THE FLAG

Section 2 of the federal flag code states that:

It is the universal custom to display the flag only from sunrise to sunset on buildings and stationary flagstaffs in the open. However, the flag may be displayed at night upon special occasions when it is desired to produce a patriotic effect.

It should also be displayed on all days when the weather permits, especially on:

New Year's Day (January 1)
Inauguration Day (January 20)
Lincoln's Birthday (February 12)
Washington's Birthday (February 22)
Armed Forces Day (3rd Saturday in May)
Easter Sunday
Mother's Day (2nd Sunday in May)
Memorial Day (half staff until noon - May 30)
Flag Day (June 14)
Independence Day (July 4)
Labor Day (first Monday in September)
Constitution Day (September 17)
Columbus Day (October 12)
Veterans Day (November 11)
Thanksgiving Day (fourth Thursday in November)
Christmas Day (December 25)

... and such other days as may be proclaimed by the President of the United States, the birthdays of the States; and on State holidays.

The flag should be displayed daily, weather permitting, on or near the main administration building of every public institution ... every polling place on election days ... and during school days in or near every schoolhouse.