OnSunday, December 21, 2025, you're bound to hear about the winter solstice. But what exactly is it? It's the shortest day of the year. To be more precise, on this day, the sun is at its lowest point of the year. This astronomical event is explained by the tilt of the Earth's axis of rotation relative to the plane of its orbit.
This date also marks the first day of winter, although meteorological winter begins earlier. "While the astronomical or calendar seasons begin with the equinoxes (spring and fall) and solstices (summer and winter), in meteorology, they begin earlier and correspond to periods of three full months," explains Météo France, which indicates that meteorological winter thus begins on December 1 and ends on February 28 or 29. But officially, from an astronomical point of view, winter this year begins onSunday, December 21, 2025, at3:03 p.m. and 1 second UTC, to be precise. This is according tothe Institute of Celestial Mechanics and Ephemeris Calculation.
But there is some good news to consider with this winter solstice. Starting on December 21, 2025, the days will get longer, and we will gain extra minutes of daylight each day until the first day of summer. This means that the sun will rise earlier and set later. As La Chaîne Météo reveals, " we will have gained 1 minute of daylight by the end of the year."
The specialized site also details the difference between the winter solstice and theequinox, i.e. when the duration of daylight is equal to that of night. Again, this phenomenon is made possible by " the tilt of the Earth's axis ". In winter, this tilt reduces our star's exposure to the sun, favoring the southern hemisphere.
In general, the winter solstice takes place on December 21, as was also the case in 2024. However, in 2023, the winter solstice fell on December 22. So how can we explain this shift in the winter solstice? To do so, we need to look at the calendar established bythe Paris Observatory's Institute of Celestial Mechanics and Ephemeris Calculation, which has compiled a list of winter solstices between 1583 and 2999! Depending on the year, the winter solstice can fall on December 21 or 22, or even December 20, as will be the case in 2080, or December 23, as was the case in 1903.
