Overview
Midnight is the moment or short interval that marks the change from one calendar day to the next. In everyday civil time it is usually represented as 00:00, the start of a new day on clocks and digital displays. As a temporal landmark it contrasts with solar noon, when the Sun reaches its highest point in the sky.
Meanings and distinctions
The word "midnight" can refer to different technical ideas. Civil midnight is the clock-based instant at 00:00 in a given time zone. Astronomical or solar midnight is the time when the Sun is at its lowest point relative to the local meridian, which does not always coincide with 00:00 because of time zones and daylight saving time.
Timekeeping and standards
Digital systems and calendars commonly treat 00:00 as the start of the calendar day; some standards such as ISO 8601 allow 24:00 as an alternative to denote the end of a day and 00:00 the beginning. Computers increment the date at 00:00 local time, so scheduling and logging often reference that instant precisely to avoid ambiguity.
Legal, administrative, and practical issues
Because "midnight" can be ambiguous in legal contexts, contracts and laws sometimes specify 23:59 or 00:00:00 to make deadlines exact. Time zone boundaries, daylight saving changes and leap-second adjustments can also affect how midnight is applied in practice.
Cultural and symbolic roles
Midnight is widely used as a symbolic threshold in rituals and celebrations (for example New Year’s transitions), curfews and folklore (witching hour), and literature as a motif of ending and beginning.
Summary and common confusions
- 00:00 typically marks the start of the calendar day.
- Solar/astronomical midnight differs from civil midnight.
- Expressions like "12:00 AM" may cause confusion; many authorities prefer 00:00 or 11:59 PM to be explicit.