Fall Equinox 2025: When Is the First Day of Fall?
The fall equinox will occur on September 22, 2025, in the Northern Hemisphere, marking the official start of autumn. In the Southern Hemisphere, the next fall equinox will arrive next year — on March 20, 2026. To check the exact local time of the equinox for your location, use the free Sky Tonight app. Let’s take a closer look at this celestial event.
Contents
- What is the autumn equinox?
- When is the first day of fall 2025?
- What time is the autumn equinox?
- Full Moon and autumn equinox
- Aurora borealis and autumn equinox
- Zodiacal light and autumn equinox
- F.A.Q.
- Autumnal equinox 2025: Bottom line
- What is it?
The autumnal equinox (as well as spring equinox) is the moment when neither of the Earth’s hemispheres is inclined towards or away from the Sun.
- When is it?
The upcoming autumnal equinox will occur on September 22, 2025, in the Northern Hemisphere. After that, the next autumnal equinox will take place on March 20, 2026, in the Southern Hemisphere.
- Why is it important?
In astronomy, the autumnal equinox marks the change of seasons — the end of summer and the beginning of fall. People from different parts of our planet celebrate this day with different traditions and festivals.
What is the autumn equinox?
Equinoxes happen when the Earth’s hemispheres aren’t tilted towards or away from the Sun. As a result, the Sun stays right above the equator, giving both hemispheres almost the same amount of sunlight.
There are two equinoxes a year — spring and autumnal ones. Once the autumnal equinox happens, the relevant hemisphere (the northern one in September and the southern one in March) is tilting away from the Sun. This leads to fewer daylight hours there, with the Sun rising later and setting earlier. The hemisphere will keep tilting away until it reaches the farthest point from the Sun at the winter solstice.
When is the first day of fall 2025?
In the Northern Hemisphere, fall begins on September 22, 2025, at 18:20 GMT. The date of the autumnal equinox in the Northern Hemisphere can vary from September 21 to 24. In the 21st century, September 22 is the most common first day of fall, happening 76 times.
In the Southern Hemisphere, fall began on March 20, 2025, at 09:01 GMT. The next autumnal equinox in this region will take place on March 20, 2026, at 14:46 GMT. The date of the autumnal equinox in the Southern Hemisphere can fall between March 19 and 21. Throughout the 21st century, March 20 will be the most common equinox day, happening 78 times. On March 21, it occurs only twice, and the remaining 20 times, it takes place on March 19.
Keep in mind that the dates mentioned are based on Greenwich Mean Time (GMT), and the equinox date might differ in various time zones.
This approach is based on the astronomical method of determining the seasons. There is another method of determining the seasons — meteorological. It suggests that autumn begins on September 1 (or March 1 in the southern latitudes). This approach relies on yearly temperature patterns. It aligns with the Gregorian calendar and employs consistent dates to evenly divide a year into four quarters.
What time is the autumn equinox?
In the Northern Hemisphere, the autumnal equinox will take place on September 22, 2025, at 18:20 GMT.
In the Southern Hemisphere, the next autumnal equinox will occur on March 20, 2026, at 14:46 GMT.
The exact equinox time for your location depends on your time zone. Here are the autumn equinox timings for different time zones in the Northern Hemisphere in 2025:
- British Summer Time (BST, GMT +1): September 22, 07:20 p.m. BST
- Central European Summer Time (CEST, GMT +2): September 22, 08:20 p.m. CEST
- Eastern European Summer Time (EEST, GMT +3): September 22, 09:20 p.m. EEST
- Moscow Standard Time (MSK, GMT +3): September 22, 09:20 p.m. MSK
- China Standard Time (CST, GMT +8): September 23, 02:20 a.m. CST
- Japan Standard Time (JST, GMT +9): September 23, 03:20 a.m. JST
- Eastern Daylight Time (EDT, GMT -4): September 22, 02:20 p.m. EDT
- Pacific Daylight Time (PDT, GMT -7): September 22, 11:20 a.m. PDT
If you want to know exactly when the event will happen where you live, try the Sky Tonight app. Just open the search window in the app and type "equinox". You'll see the equinoxes’ dates and times, all set for your local time.
When does Daylight Saving Time end?
As you can see, two of the time zones listed above contain the word "daylight". Daylight Saving Time is when we move our clocks ahead by one hour in the summer and then back again in the fall. The main idea is to make better use of natural daylight. When we move the clocks ahead in spring, we get more daylight in the evenings, and when we move them back in fall, we get more daylight in the mornings.
You might expect Daylight Saving Time to end right with the autumn equinox, but that’s not the case. In many regions of the Northern Hemisphere, the equinox occurs while DST is still in effect. For example, in the United States, Daylight Saving Time starts on the second Sunday in March and ends only on the first Sunday in November.
Full Moon and autumn equinox
Even though you can't directly observe the equinox, you can observe some effects it brings. For example, you might notice that the Full Moon rises earlier around the time of the autumnal equinox compared to other times. This happens because the angle of the Moon's path in the sky and the tilt of the Earth's axis align during this period.
In the Northern Hemisphere, the two Full Moons that are closest to the autumn equinox in 2025 occur on September 7 and October 7. You can find more details about the September Full Moon and October Full Moon in our dedicated articles.
Aurora borealis and autumn equinox
Another visible outcome of an equinox is the increasing activity of auroras — both the aurora borealis (Northern Lights) and the aurora australis (Southern Lights). Around equinoxes, your chances of seeing auroras increase in both hemispheres.
To simplify it, during equinoxes, the Earth's magnetic poles are situated in a way that they align well with the solar wind (the cause of the auroras), making it more likely for the Earth to "accept" it.
Zodiacal light and autumn equinox
The time around the equinoxes in both hemispheres is the best for viewing the zodiacal light — a rare and beautiful celestial phenomenon that looks like a hazy pyramid of light rising from the horizon. It occurs just after dusk near the vernal equinox and just before dawn near the autumnal equinox.
We see the zodiacal light because the sunlight reflects from dust grains orbiting the Sun in the inner Solar System. Learn more about where these dust grains come from and how to see the zodiacal light from our dedicated article.
F.A.Q.
Are day and night truly equal on the equinox?
They're quite close to being equal, but not precisely. For example, on September 22, 2025, in New York, USA, daylight will last for about 12 hours and 8 minutes. There are two reasons behind this slight discrepancy — first, atmospheric refraction (that delays sunsets by about 8 minutes), and second, the specific definition of sunset and sunrise. For a visual explanation of why day and night aren't exactly equal during equinoxes, you can check out our infographic about equinoxes.
By the way, there are indeed days when day and night are exactly the same length. They're called equiluxes and usually occur a few days after the autumnal equinox. However, the exact dates for equiluxes can vary for different locations. Learn more about equiluxes from our article.
Do other planets have equinoxes and solstices?
Except for Mercury, all planets in our Solar System tilt on their axes, leading to their own equinoxes and solstices. Venus and Jupiter have small tilts of 2.6° and 3.1°, respectively. Venus, with its quicker orbit, experiences these events every few months, while Jupiter's slower orbit means they occur roughly every three Earth years.
Mars, Saturn, and Neptune share tilts similar to Earth's: 25.2°, 26.8°, and 28.3°. Saturn's equinoxes present its rings edge-on to Earth.
Uranus stands out with its extreme tilt of 98°. It causes day and night to switch every 17 hours around equinoxes, but during its summer and winter, half of the planet remains either in darkness or daylight.
What's the difference between an equinox and a solstice?
There are three key differences between an equinox and a solstice:
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Day and night balance vs. longest day or night. Equinoxes mark nearly equal lengths of day and night, while solstices bring the longest day or night of the year, depending on the season.
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Timing of events. Equinoxes occur in March and September, while solstices take place in June and December.
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Tilt angle. Equinoxes happen when the Earth's hemispheres aren't tilted toward or away from the Sun. Solstices occur when one hemisphere is tilted maximally toward the Sun (summer solstice) or away from it (winter solstice).
Now that you've gone through this article, you should be a pro at understanding equinoxes. Take our quiz to test yourself! If you paid attention while reading, you'll find it easy to tell the difference between solstices and equinoxes.
Autumnal equinox 2025: Bottom line
In the Northern Hemisphere, the autumnal equinox happens on September 22, 2025, at 18:20 GMT. In the Southern Hemisphere, the autumnal equinox already occurred on March 20, 2025, at 09:01 GMT, and the next one will take place on March 20, 2026, at 14:46 GMT. This event signals the shift from summer to fall. Following the equinox, temperatures drop, and the nights grow longer. During the equinox, the duration of daylight and nighttime is almost the same.
