In many cultures, September is associated with back-to-school season, harvest festivals like Oktoberfest (which actually starts in September), and the Jewish New Year (Rosh Hashanah).
| Aspect | Astronomical Fall | Meteorological Fall | Perceptual / Cultural Fall | | :--- | :--- | :--- | :--- | | | Late Sept to Late Dec | Sept, Oct, Nov | Sept, Oct, Nov | | Start Date | Sept 21-24 | Sept 1 | After Labor Day (US) or school starts | | End Date | Dec 20-23 | Nov 30 | Before Thanksgiving or first snow | | Based On | Earth's orbit & tilt | Annual temperature cycle | Sights, sounds, & traditions | | Key Feature | Autumnal Equinox | Consistent data months | Fall foliage & harvest holidays |
Beyond the scientific definitions, most people define fall by what they see, feel, and do. This "perceptual fall" often doesn't match the strict calendar. For example:
The answer depends on who you ask—an astronomer, a meteorologist, or a cultural historian. While a standard calendar might point to a specific three-month block, the reality of autumn is far more nuanced. In this comprehensive guide, we will break down the official definitions, regional variations, and seasonal markers that actually determine when fall arrives and leaves. what months are the fall
This holds true for both meteorological definitions and the general public understanding. Astronomical definitions use the same months but with specific start and end dates that shift slightly each year.
The definition of fall (or autumn) depends on whether you use the meteorological calendar or the astronomical one. In the Northern Hemisphere, it generally spans from or December . 1. Meteorological Fall
Under this definition, fall can last longer or shorter than three months depending on the specific climate of a region. In the Arctic, "fall" might only last a few weeks as summer instantly transitions into winter. In tropical regions near the equator, there is essentially no fall at all; the seasons are usually divided between "wet" and "dry" rather than spring, summer, fall, and winter. For example: The answer depends on who you
Because Earth's orbit isn't perfectly synchronized with our calendar, the exact dates shift slightly each year. This means astronomical fall varies in length from about 89 to 93 days.
The March equinox (around March 20–21) marks the astronomical start of autumn. In countries like Australia, New Zealand, South Africa, and parts of South America, March brings harvest festivals and a shift toward cooler weather.
In this view, fall begins when the environment decides it has arrived. This holds true for both meteorological definitions and
📆 (used for climate records and forecasting): September, October, November → These are the three full months with the most consistent autumn-like temperatures.
Seasonality is not uniform across all ecosystems. Cultural traditions and local climates dictate how people perceive the fall months globally.
The astronomical start of fall (the autumnal equinox) changes slightly each year because the Gregorian calendar (365 days) isn't perfectly synced with Earth's orbital period (approximately 365.24 days). This is why some years you might see fall begin on September 22, and other years on September 23. In rare cases, it can occur on September 21 or 24.