The winter solstice, also called the hibernal solstice, occurs when either of Earth’s poles reaches its maximum tilt away from the Sun. This happens twice yearly, once in each hemisphere (Northern and Southern). For that hemisphere, the winter solstice is the day with the shortest period of daylight and longest night of the year, when the Sun is at its lowest daily maximum elevation in the sky. Either pole experiences continuous darkness or twilight around its winter solstice. The opposite event is the summer solstice…
Since prehistory, the winter solstice has been a significant time of year in many cultures, and has been marked by festivals and rituals. It marked the symbolic death and rebirth of the Sun; the gradual waning of daylight hours is reversed and begins to grow again. Some ancient monuments such as Newgrange and Stonehenge are aligned with the sunrise or sunset on the winter solstice.