Here’s When Fall Officially Begins in 2026
For millions of people in the Northern Hemisphere, the first day of fall arrives with the September equinox. In 2026, however, the exact calendar date depends on where you are in the world and which definition of fall you use.
Astronomically, fall begins when the September equinox occurs. In 2026, that moment falls on September 23 at 00:05 UTC, according to the U.S. Naval Observatory. In U.S. time zones west of Greenwich, the event occurs on September 22. In India, the equinox takes place at 5:35 a.m. IST on September 23.
That means someone in New York can experience the astronomical start of fall on September 22, while someone in India reaches the same seasonal moment on September 23.
Is today the first day of fall in 2026?
If you are in the Northern Hemisphere, astronomical fall begins at the September equinox. In 2026, the equinox occurs at 00:05 UTC on September 23, which means the local calendar date ranges from September 22 to September 23 depending on the time zone.
NASA identifies September 22 as the date when the September equinox occurs for many locations in the United States, while the U.S. Naval Observatory gives the global astronomical event as September 23 at 00:05 UTC.
For example:
|
Location |
Local date and time of 2026 September equinox |
|
New York |
September 22, 8:05 p.m. EDT |
|
Los Angeles |
September 22, 5:05 p.m. PDT |
|
London |
September 23, 1:05 a.m. BST |
|
India |
September 23, 5:35 a.m. IST |
|
UTC |
September 23, 00:05 UTC |
The underlying astronomical event is the same everywhere. Only the local clock and calendar date change.
What exactly happens at the September equinox?
The September (Northern Hemisphere) equinox is when the Sun’s apparent position passes through the plane of Earth’s equator as Earth proceeds along itsapex annual orbit about the Sun.
The seasons are due to the tilt of the Earth’s axis as the planet orbits the Sun. The September equinox occurs occurring just after the solstice of the summer of the Northern Hemisphere as the apparent path of the Sun starts to move southward from the Earth’s equator.
After the September equinox:
- Daylight gradually decreases across the Northern Hemisphere.
- Nights become progressively longer.
- The Sun’s apparent path moves farther south.
- Spring begins in the Southern Hemisphere.
- The Northern Hemisphere moves toward its winter solstice in December.
NASA describes September 22, 2026, as the point when fall begins in the Northern Hemisphere and spring begins in the Southern Hemisphere.
Why is the first day of fall not always September 22?
The astronomical calendar does not assign the equinox to a fixed calendar date every year. The timing depends on Earth’s orbit and the way the calendar year is structured.
The September equinox can occur on September 22, 23 or, less commonly, September 21 or 24 depending on the year and time zone. The event itself is a precise astronomical moment rather than an entire day.
In 2026, the U.S. Naval Observatory calculates the September equinox at 00:05 Universal Time on September 23. Because locations around the world use different time zones, the same event occurs during the evening of September 22 in parts of North America and after midnight on September 23 across much of Europe and Asia.
This is why two calendars can appear to give different dates for the start of fall without either being incorrect.
Is September 1 the first day of fall?
September 1 is the beginning of meteorological fall, while the September equinox marks the beginning of astronomical fall in the Northern Hemisphere.
Meteorologists divide the year into three-month seasons based on the calendar. Under this system, fall runs from September 1 through November 30 in the Northern Hemisphere.
Astronomical seasons instead follow Earth’s position relative to the Sun. Fall begins with the September equinox and ends with the December solstice. NOAA distinguishes the two systems because they serve different purposes: meteorological seasons make it easier to analyse weather and climate data consistently, while astronomical seasons follow Earth’s changing position in its orbit.
|
Season system |
Fall begins |
Fall ends |
|
Meteorological |
September 1 |
November 30 |
|
Astronomical |
September equinox |
December solstice |
So, if someone says fall started on September 1, they are using the meteorological definition. If they say fall starts at the September equinox, they are referring to the astronomical definition.
Both are established systems.
Does the equinox mean day and night are exactly equal?
Not quite.
The term equinox is derived from Latin roots indicating “equal night” still the period of day and night are not equal at every place on the date of an equinox.
The Earth’s atmosphere bends the light of the sun leading to an effect called atmospheric refraction. The location of the Sun can be observed through an atmospheric refraction and that means the sun can be observed even when appears to be below horizon based on geometric calculations. The apparent size of the Sun also influences the circumstances of the events of sunrise and sunset.
The actual date of equal daylight and darkness also varies with latitude. At many locations, the equal-day-and-night date occurs several days away from the equinox.
The U.S. Naval Observatory notes that at about 40 degrees north latitude, for example, equal day and night around the September season occurs around September 26 rather than on the equinox itself.
That makes the common phrase “equal day and night” a useful description of the equinox, but not a precise statement for every location on Earth.
What happens to daylight after the September equinox?
As the days are growing shorter for the Northern Hemisphere after the September equinox eventually reaching the December solstice.
The change is not instantaneous and is slow. The amount of sunlight loss per day varies greatly with where you are located. There is a much larger change at higher latitudes, and less change near the equator
Meanwhile, the Southern Hemisphere is moving in the other direction. It is moving toward the summer solstice of the southern hemisphere in December.
This difference is purely due to the tilt of the Earth’s axes on the Sun’s.
What is the difference between fall and autumn?
There is no difference in the season itself. Fall and autumn are two names for the same season.
“Autumn” is widely used in British English and many other varieties of English, while “fall” is especially common in American English. Both terms refer to the transition between summer and winter in the Northern Hemisphere.
The astronomical event is commonly called the September equinox, autumnal equinox or fall equinox.
Using “fall” or “autumn” therefore does not change the date or astronomical event being described.
When does fall end in 2026?
Astronomical fall in the Northern Hemisphere ends at the December solstice.
The U.S. Naval Observatory lists the 2026 December solstice at 20:50 UTC on December 21. That event marks the beginning of astronomical winter in the Northern Hemisphere and astronomical summer in the Southern Hemisphere.
Meteorological fall ends earlier, on November 30.
This creates two different timelines:
- Meteorological fall: September 1 to November 30
- Astronomical fall: September equinox to December solstice
The distinction is useful because weather agencies and astronomers are measuring different things.
The 2026 fall timeline at a glance
For anyone wondering when the season officially changes, the key dates are:
September 1, 2026: Meteorological fall begins in the Northern Hemisphere.
September 22, 2026: The September equinox occurs locally on this date in parts of North and South America, including New York and Los Angeles.
September 23, 2026, 00:05 UTC: The astronomical equinox occurs worldwide at this precise moment.
September 23, 2026, 5:35 a.m. IST: The equinox occurs in India.
December 21, 2026, 20:50 UTC: The December solstice arrives, ending astronomical fall in the Northern Hemisphere.
So, is today the first day of fall?
The answer depends on your location and the definition of the season.
For the Northern Hemisphere, the astronomical first day of fall is tied to the September equinox. In 2026, that equinox occurs at 00:05 UTC on September 23. In parts of the Americas, the event falls on September 22 because of the local time zone; in India and much of Asia, it falls on September 23.
Meteorologically, fall has already been underway since September 1.
For people south of the equator, the situation is reversed: the September equinox marks the beginning of spring, not fall.
The simplest answer, therefore, is this: the first day of astronomical fall in 2026 is the September equinox, and the local calendar date depends on where you are in the world.
