This year, the autumn equinox falls on Wednesday, September 23, 2026. A key date many night owls are eagerly awaiting, while sun lovers dread it. And for good reason: starting on September 23, 2026, we officially enter autumn and will lose about 4 minutes of sunshine each day on average until the winter solstice on December 21.
But what exactly is the equinox? It’s an astronomical moment when the length of the day equals the length of the night. Each year, two equinoxes occur: the first between March 19 and 21, when we move from winter to spring in the northern hemisphere, and the second between September 21 and 24, when we leave summer and enter autumn, again in the northern hemisphere.
The Autumn Equinox 2026 falls on Wednesday, September 23, precisely at 00:05 UTC (Coordinated Universal Time, i.e., 02:05 in metropolitan France), according to the Institute of Celestial Mechanics and Ephemeris Calculations (IMCCE). At that moment, the Sun will cross the zenith of the Earth's equator, then rise almost due east and set due west.
Last year, the autumnal equinox occurred on September 22, one day earlier. In 2023 the autumnal equinox fell on September 23, just as in 2022. But then, why are the date and time never the same? You have to look to our Gregorian calendar to understand better. Here, a year lasts 365 days. Yet in reality, the Earth takes exactly 365 days, 5 hours and 48 minutes to complete one orbit around the Sun. So, to catch up with this drift, we add an extra day every four years, the famous leap years. A shift that thus changes the dates and times of the equinox.
Note that the next autumn equinox, scheduled for September 21, will take place in 2092, while the one on September 24 is scheduled for 2303!
