When Does Autumn 2023 Officially Begin?

Autumn, also known as fall, is one of the four temperate seasons that occurs annually. It marks the transition from summer into winter in the Northern Hemisphere. Many people look forward to fall each year, as it brings about cooler weather, beautiful fall foliage, and popular autumn activities. But when does autumn officially begin in 2023?

The Autumnal Equinox Marks the Start of Fall

The exact date when autumn starts depends on when the autumnal equinox occurs. The autumnal equinox, also called the September equinox or fall equinox, signifies the moment when the Sun crosses the celestial equator heading southward. It marks the point when day and night are of equal length, usually falling on September 22nd or 23rd.

In 2023, the September equinox occurs on Friday, September 22nd at 9:04 PM EDT. This precise moment is when astronomical fall begins in the Northern Hemisphere, meaning fall 2023 will officially start on 9/22. The autumnal equinox occurs at the same moment worldwide, though clock times reflect different time zones.

After the autumnal equinox, the number of daylight hours continues to decrease as the Northern Hemisphere tilts farther away from the Sun. Areas north of the equator begin to experience shorter days and longer nights.

The Different Dates for Meteorological and Calendrical Fall

While astronomical fall begins on a fixed date, there are also other dates used to mark the start of the fall season:

Meteorological fall – September 1st based on the annual temperature cycle and linking it to our Gregorian calendar.
Calendrical fall – September 1st in the United States, matching the start of the academic year for schools and universities.

So although astronomical fall doesn’t officially begin until the autumnal equinox, September 1st is also commonly used as the start of the fall season.

Cooler Temperatures Arrive in Fall

One of the most noticeable changes in weather during fall is the drop in temperatures. In the Northern Hemisphere, cooler weather usually starts to set in by September and continues through November.

Several factors contribute to the decrease in temperatures and cooler weather in the fall:

The tilt of the Earth away from the Sun, resulting in less direct sunlight and solar heating.
Shorter days and longer nights, allowing more time for cooling overnight.
Polar and arctic air masses expanding southward earlier in the season.
Increasing cloud cover reflecting more sunlight away from Earth’s surface.
The ground and water losing stored heat from the summer months.

Temperature changes from summer to fall vary by location. But on average, temperatures can drop 10-15°F (5-8°C) from August to November for most of the United States and other Northern Hemisphere mid-latitude locations.

Fall Foliage Comes Alive with Vibrant Colors

One of the quintessential signs of fall is the changing colors of the leaves on deciduous trees. Fall foliage peaks in vibrancy anytime between mid-September and early November depending on your location and tree species.

The bursts of orange, red, yellow, purple, and brown during autumn occur because of chemical changes in the leaves:

Throughout spring and summer, leaves maintain their green pigment chlorophyll to perform photosynthesis.
As autumn approaches, decreasing daylight and colder weather cause the chlorophyll in leaves to break down faster than it can be replaced.
This allows carotenoids, the pigments responsible for yellows and oranges, to show through.
Cool nights trigger the production of anthocyanins, adding bright reds and purples.
The brown fall colors come from tannins already present in the leaves.

Popular Activities to Enjoy the Fall Season

The cooler days and stunning colors of fall inspire many popular outdoor autumn activities. Here are some top things people look forward to doing every fall:

Picking apples or going on hayrides at local apple orchards
Hiking through the autumn woods to enjoy the fall foliage
Jumping into piles of fallen leaves
Carving jack-o-lanterns for Halloween
Tailgating and watching football games
Sipping hot apple cider and pumpkin-flavored treats
Cozying up around a bonfire to roast marshmallows

The Fall Equinox Has Significance in Culture and History

The fall equinox has long held importance in culture and history around the world:

In Greek mythology, the autumnal equinox marked when Persephone returned to the underworld with Hades for several months.
In ancient China, the autumnal equinox signaled the time to pay respects to dead ancestors during the Hungry Ghost Festival.
The equinox has significance in pagan and Wiccan traditions, marking the second harvest festival in the Wheel of the Year.
The Pyramid of the Sun in Teotihuacán, Mexico was carefully aligned so that the west face stairway pointed at sunset on the fall equinox.
The autumnal equinox occurs on the same day as the Mid-Autumn Festival in East Asia, which is celebrated by lighting lanterns and eating mooncakes.

Conclusion

While the autumnal equinox on September 22nd marks the official start of astronomical fall, meteorological and calendrical fall also begin around September 1st each year. The changing weather, fall foliage, and beloved seasonal activities make autumn an exciting time. Knowing exactly when the fall season begins helps you prepare and look forward to everything it has to offer.

FAQs about the Start of Fall

What day does fall start in 2023?

In 2023, astronomical fall starts on Friday, September 22nd, the date of the autumnal equinox. Meteorological and calendrical fall begin on September 1st.

Does fall start on the 21st or 22nd?

The autumnal equinox usually falls on September 22nd or 23rd. In 2023, the equinox, and therefore astronomical fall, starts on September 22nd.

Is September 21st the first day of fall?

No, September 21st is not the official first day of fall. The autumnal equinox that marks the start of astronomical fall is on September 22nd in 2023.

What time does fall start on September 22 2023?

On September 22, 2023, astronomical fall begins the moment of the autumnal equinox, which occurs at 9:04 PM EDT. This exact time varies slightly year to year.

Why does fall start late September?

Fall starts in late September because this is when the autumnal equinox occurs, marking the moment the Sun crosses the equator heading south. This results in equal day and night lengths to start the fall season.