Why Does Fall Begin on September 22? Discover the Surprising Reason

As the calendar flips to late September, many anticipate the arrival of fall with its crisp air and vibrant foliage. But why does the season officially begin on September 22? The answer, it turns out, is rooted in astronomy and ancient tradition-and may not be as straightforward as you think. In this article, the Bergen Record unpacks the surprising science and history behind the fall equinox, shedding light on what truly marks the start of autumn.

The Astronomical Reason Behind Fall Starting on September 22

Every year, the transition from summer to fall is marked by a moment in time known as the autumnal equinox, which typically falls on September 22. This astronomical event occurs when the sun crosses the celestial equator, making day and night roughly equal in length across the globe. Unlike popular belief that the change of seasons is tied to calendar dates alone, it is this precise alignment between Earth’s tilt and orbit around the sun that dictates the official start of fall.

Here’s why this celestial phenomenon is so significant:

Earth’s axis is tilted at approximately 23.5°, affecting sunlight distribution.
The sun appears to “stand still” at the equator before heading southward.
Daylight hours decrease, signaling a shift toward cooler temperatures.

Event

Date Range

Sun’s Position

Summer Solstice

June 20-22

Northernmost point

Autumnal Equinox

September 22-23

Crossing celestial equator

Winter Solstice

December 20-23

Here’s why this celestial phenomenon is so significant:

Earth’s axis is tilted at approximately 23.5°, affecting sunlight distribution.

The sun appears to “stand still” at the equator before heading southward.

Daylight hours decrease, signaling a shift toward cooler temperatures.

Event

Date Range

Sun’s Position

Summer Solstice

June 20-22

Northernmost point

Autumnal Equinox

September 22-23

Crossing celestial equator

How the Equinox Marks the Official Beginning of Autumn

Twice a year, Earth’s tilt and orbit align in such a way that day and night stand in perfect balance. This phenomenon, known as the equinox, signals a pivotal shift in our planet’s environmental rhythms. On this day, the sun crosses the celestial equator, leading to nearly equal hours of daylight and darkness worldwide. It is this cosmic coincidence that officially ushers in autumn, marking a transition not just in temperature, but in the natural world’s chemistry and cadence.

The equinox is more than just an astronomical event; it carries deep cultural and ecological significance. As autumn begins, observe the following changes that become apparent in the weeks ahead:

Shorter days: Daylight diminishes, inviting cooler evenings and longer nights.
Leaf color transformation: Chlorophyll production slows, unveiling vibrant reds, oranges, and yellows.
Harvest season: Many crops reach maturity, coinciding with time-honored agricultural festivals worldwide.

Event	Date	Significance
September Equinox	Sept 22/23	Balanced day and night; start of autumn
First Frost	Late Sept – Oct	Signal for plants to slow growth
Harvest Festivals	Sept – Oct	Community celebrations of the season

What This Seasonal Shift Means for Your Daily Life and Environment

As temperatures begin to dip and daylight hours shorten, the subtle transitions ushered in by the fall season bring tangible changes to both our routines and the natural world. For many, this shift signals the return to cozy layers and a reevaluation of daily habits-from adjusting heating systems to altering commute times to accommodate earlier sunsets. Gardeners and outdoor enthusiasts will notice a profound transformation in flora, as deciduous trees prepare to shed their leaves in a magnificent display of reds, oranges, and yellows, creating a picturesque but temporary landscape. This period also marks a critical juncture for wildlife, with animals increasing their foraging activities and preparing for the approaching winter months.

Understanding these changes can help individuals better adapt and contribute to environmental stewardship. Here are some key impacts to consider:

Energy Consumption: Increased heating needs result in higher energy usage; switching to programmable thermostats can optimize comfort and efficiency.
Daylight Management: Utilize natural light during shorter days to improve mood and productivity; consider investing in daylight lamps if needed.
Wildlife Awareness: Be mindful of animal habitats as creatures migrate or enter hibernation, reducing nighttime disturbances and preserving ecological balance.
Seasonal Health: Immunity can fluctuate with seasons-boost nutrition and stay active to maintain wellness during cooler months.

Aspect	Pre-Fall	Post-Fall Shift
Average Daylight	14 hours	10 hours
Average Temperature	75°F (24°C)	55°F (13°C)
Energy Use	Baseline	+20%
Tree Foliage	Green	Colorful & Shedding

In Retrospect

As the leaves begin their vibrant transformation and temperatures start to dip, understanding why fall officially begins on September 22 offers more than just a calendar date-it connects us to centuries of astronomical tradition and scientific precision. Whether you’re an avid weather watcher or simply curious about the rhythms of the seasons, this explanation sheds light on a turning point that signals nature’s grand transition. For residents of Bergen and beyond, the start of fall is not just a change in weather, but a moment grounded in the cosmic alignment that continues to captivate and surprise us all.