With a modern literal meaning of "midnight," the term witching hour refers to the time of night (3:00-4:00 am is commonly speculated) when creatures such as witches, demons, and ghosts are thought to appear and to be at their most powerful and black magic to be most effective. It may be used to refer to any arbitrary time of bad luck or in which something bad has a greater likelihood to occur (e.g., a baby crying, or a computer crashing, or stock market volatility, crimes, supernatural, etc.). The witching hour from medieval times is the time believed that witches came out to do their "unholy" practices. The time ascribed to the witching hour was generally viewed after midnight. Women caught out late at night could have been suspected of witchcraft if they did not have a legitimate reason to be out.
In several of Shakespeare's plays – specifically Macbeth and Julius Caesar – ghosts and other supernatural phenomena take place around midnight, but the term "witching hour" never appears. However, in the play Hamlet, we hear young Hamlet saying, "'Tis now the very witching time of night."
One appearance of this term is in Washington Irving's short story The Legend of Sleepy Hollow. Here, Irving uses "witching hour" and "witching time" interchangeably. Both terms reference midnight, and are used to conjure in readers a sense of supernatural anxiety. There is little evidence the term had any practical use prior to this; Irving may have coined the phrase after having grown up around New England and touring areas where the Salem Witch Trials took place.