The winter solstice is the day with the shortest daylight and the longest night in the Northern Hemisphere. On this date, the Sun reaches its lowest noon height in the sky for the year, meaning it follows its lowest daily arc and sets earlier. Astronomically, the winter solstice is often considered the start of winter.
When does the winter solstice happen?
It usually falls on December 21 or December 22. The exact date depends on how Earth’s orbit and the calendar align (including leap years and the precise timing of Earth’s movement).
Why is it the “longest night”?
Earth’s axis is tilted. During the Northern Hemisphere winter, the hemisphere is tilted away from the Sun, reducing daylight. The winter solstice is the point when that effect reaches its maximum.
Solstice vs equinox
- Solstice: The two extremes of daylight (summer and winter).
- Equinox: The two points when day and night are roughly equal (spring and autumn).
What about the Southern Hemisphere?
When the Northern Hemisphere has the winter solstice, the Southern Hemisphere experiences the summer solstice—the longest day of the year there.
Cultural meaning
Many traditions connect the winter solstice with the idea of “the return of light.” Celebrations linked to Yule, Saturnalia, and modern winter festivals are often discussed in this context.
In short
The winter solstice marks the longest night in the Northern Hemisphere and the turning point after which daylight gradually increases.