Winter Solstice 2025: shortest day, longest night of year marks beginning of astronomical winter

The winter solstice of 2025, occurring today, marks the beginning of the astronomical winter, as well as the start of the coldest three months of the year in the Northern Hemisphere. Today is the shortest day of the year, with less than nine hours, and the following night will be the longest of the year. Starting from December 22, the day will begin to lengthen and will become equal with the night at the spring equinox in March 2026.

The winter solstice is related to the apparent annual movement of the Sun on the celestial sphere, which is the result of the Earth's actual motion around the Sun.

During the winter solstice, the northern hemisphere of the planet is at the farthest point from the sun. On the other hand, in the southern hemisphere, December 21 marks the summer solstice or the day when the southern part of the planet is at the closest point to the Sun.

Since prehistoric times, the winter solstice has been seen as a significant period of the year in many cultures and has been marked by festivals and rituals. The seasonal significance of the winter solstice lies in the reversal of gradually lengthening nights and shortening days.

In pagan culture, the winter solstice meant the birth of the Sun, symbolizing a new process of the four seasons.

The winter solstice was celebrated by the ancient Dacians with the sacrifice of a pig, a tradition that has endured to this day and is now associated with Christmas. Through this ritual, the Dacians aligned themselves with the light in the battle against darkness on the shortest day of the year.