vintersolhverv

Vintersolhverv, or the winter solstice, is the annual astronomical event marking the point at which the Sun reaches its southernmost position in the sky for observers in the Northern Hemisphere. It yields the shortest day and longest night of the year and occurs once a year, typically on December 21 or 22; in the Southern Hemisphere the dates are inverted, around June 20 or 21.

The event is caused by Earth's axial tilt of about 23.44 degrees relative to its orbit around the Sun. When the Sun's declination is about -23.44 degrees at local solar noon, the Sun is at its lowest maximum elevation in the sky. On that day, the Sun's path is the lowest across the sky, and daylight is minimized.

After the solstice, the Sun's daily arc begins to rise again, and daylight gradually lengthens. The exact daylight hours depend on latitude; at high latitudes, the solstice can coincide with very short days or even polar night, while near the equator the length of day remains close to twelve hours.

Culturally, vintersolhverv has been observed in many societies as a turning point of winter and a time of celebration. Traditions around solstice include lights, feasts, and seasonal rites. In Danish and Norwegian contexts the term vintersolhverv is used to denote the occasion, which has historically been linked to midwinter festivities and to the timing of Christmas celebrations.

Etymology: The word vintersolhverv is composed of winter, sun, and turning, reflecting its meaning as the turning point of the Sun in the winter sky.