Why are the days so short?
The winter solstice is an astronomical phenomenon that occurs when the axis of rotation of the Terre incline the North Pole at its farthest point from Soleil. In other words, the sun reaches its lowest position in the sky, making the days shorter.
However, all is not so gloomy: the day after December 21the days will begin gradually lengthen until summer solsticescheduled for June 21, 2024.
A complex and variable phenomenon
The solstice d’hiver does not take place on exactly the same date every year. This variation is explained by the difference between our calendar year (365 days) and the actual duration of the rotation of the Terre around the Sun (365 days, 5 hours and 48 minutes). This is why we have leap years every four years, in order to readjust the calendar.
In 2024, the solstice occurs precisely at the instant when the apparent geocentric longitude of the Sun reaches 270°according to the Institute of Celestial Mechanics and Ephemeris Calculation (IMCCE).
The paradox of sunrise and sunset times
Since the December 11the Sun sets a little later each day. However, the days keep getting shorterbecause the sunrise also shifts to a later time. This phenomenon stabilizes from December 21the moment when the days finally gain length.
Solstices and seasons
THE solstices and the equinoxes punctuate the cycle of the seasons:
THE solstices mark the longest (summer) and shortest (winter) days. They take place on June 21 and September 21. THE equinoxes (spring and fall) occur when day and night are of equal length. These are March 21 and September 21.
