midnight

Midnight is the period of time at the transition between one day and the next, conventionally defined as 00:00 (twelve o’clock at night) in civil time. It marks the start of a new calendar day by most timekeeping systems. The term derives from Old English midniht, from mid (middle) and niht (night). Historically, the precise moment of midnight could vary with local measurements and clocks; standardization came with mechanical clocks and later time zones and daylight saving.

Astronomically, midnight can also refer to astronomical midnight, the time when the Sun is geometrically at its lowest apparent position in the sky. This is typically defined as the moment when the Sun is 18 degrees below the horizon, though the exact moment depends on latitude and season.

Localization matters: civil midnight (00:00) is used for daily life; solar midnight is the time halfway between sunset and sunrise when the Sun is at its lowest point in the sky; these times shift with longitude, time zones, and daylight saving time.

In culture, midnight is a frequent motif in folklore, literature, and media, often associated with mystery, transition, and danger. Phrases such as “midnight hour” or “midnight snack” reflect its cultural prominence. The word appears in many titles of works across literature, film, and music, and some genres or groups use the name Midnight or The Midnight. See also: Witching hour; New day; Timekeeping.