Autumn
The beginning of autumn
Autumn 2025 in the northern hemisphere will begin on September 22 at 20:19 Spanish mainland time according to calculations by the National Astronomical Observatory (National Geographic Institute - Ministry of Transport and Sustainable Mobility). This season will last approximately 89 days and 21 hours, and will end on December 21 with the onset of winter.
The beginning of autumn in the northern hemisphere is defined by the moment when the Earth passes through the point in its orbit from which the centre of the Sun crosses the celestial equator in its apparent southward motion. On the day when this happens the length of day and night practically coincide. This is also called the autumnal equinox.
As autumn begins in the northern hemisphere, spring begins in the southern hemisphere.
The sky during autumn 2025
At the beginning of autumn, the sky after sunset, we will be able to see Mars and Saturn. Mercury will make an appearance a few days after. Mercury and Mars will be visible until mid-November.
Sunrises, on the other hand, will be preceded by Venus and Jupiter. The first will be visible until late November, when Mercury will take its place.
As for the stars and constellations visible at dusk in autumn, the summer triangle formed by Deneb from the Swan, Vega from the Lyre and Altair from the Eagle will remain visible during the early part of the season, although gradually lower above the western horizon. As the months progress, the constellations Pegasus, Andromeda and Perseus, will emerge in the east, and at the end of the season the constellations Taurus and Orion will appear, reaching their peak during the winter nights.
Other phenomena of astronomical interest during the autumn of 2025 will be the Draconids, meteor shower, whose maximum is expected around October 8, the Orionids, with a maximum around October 21, the Leonids, with a maximum around November 17, and the Geminids, with a maximum around December 14. The autumn full moons will occur on October 7, November 7 and December 5.
During the autumn 2025 there will be no solar or lunar eclipses.
Time change
Although both the European Parliament and the Commission have spoken out in favour of eliminating time changes in the future, there is still no final decision on the matter. Therefore, the traditional time change on the last Sunday in October will remain in place for 2025. On that day, October 26, the clocks will be set back by one hour to 2 a.m. at 3 a.m. on the Spanish mainland. In the Canary Islands, 2 a.m. will be changed to 1 a.m.
Some interesting facts about autumn
The beginning of autumn can occur, at most, on four different dates in the calendar (from 21 to 24 September). Throughout the 21st century, autumn will begin on 22 and 23 September (official Spanish date), with the earliest beginning in 2096 and the latest in 2003. The variations from year to year are due to the way the sequence of calendar years (some leap years, some not) fits in with the length of each orbit of the Earth around the Sun.
Early autumn is the time of the year when day length shortens most rapidly. At Spanish mainland latitudes, the sun rises more than a minute later in the morning than the previous day, and sets more than a minute earlier in the evening. As a result, at the beginning of autumn, the time the Sun spends above the horizon decreases by almost three minutes each day.
For more information on the year's astronomical phenomena, please consult the Almanak of the Astronomical Observatory, published by the National Geographic Institute.
Information provided by the National Astronomical Observatory (IGN, Ministry of Transport and Sustainable Mobility). Reproduction in whole or in part is authorised provided the source is acknowledged.