Why are the Library lights flashing? The Library lights are flashed on two different occasions each evening to warn Library users that the Library is about to close. They are flashed 30 minutes prior to closing and again 10 minutes before closing. This is done to ensure that you have enough time to complete any online quizzes, to save your work appropriately and to check out books before the Circulation Desk closes. For more information about closing times, check the Library Hours page.