When Does Autumn Start [patched] Jun 2026

There is no "wrong" answer here.

In the Northern Hemisphere, meteorological autumn begins on September 1st and ends on November 30th. This definition is based on the annual temperature cycle and the climatological patterns of the region. Meteorologists use this definition to make it easier to compare data from year to year.

Are we bound by the astronomical calendar, or do we stick to the meteorological one? And why are the dates different in the first place? when does autumn start

Note: If you live in the Southern Hemisphere (like in Australia or Brazil), these dates are flipped. Their autumn begins in March!

However, if you're interested in the astronomical definition of autumn, the season officially begins when the sun crosses the celestial equator from north to south. This event, known as the autumnal equinox, typically occurs around September 22nd or September 23rd in the Northern Hemisphere. On this day, day and night are approximately equal in length, marking the beginning of autumn. There is no "wrong" answer here

On this day, the sun crosses the celestial equator. For us in the Northern Hemisphere, the sun moves southward. The result is a day where the hours of daylight and darkness are almost perfectly equal. From this point forward, the nights grow longer than the days, sending us hurtling toward winter.

Under this system, and ends on November 30th. Meteorologists use this definition to make it easier

It is officially "sweater weather" season. But if you are the type of person who takes out the calendar to mark the occasion, you might notice something confusing. Depending on where you live or who you ask, the start date of autumn changes.

Understanding when autumn starts is more than just a calendar curiosity. It dictates agricultural schedules, energy consumption patterns as heating systems are turned on, and cultural traditions. Whether you are waiting for the "official" equinox or the first of September, autumn represents a season of reflection, preparation, and natural beauty. If you want to plan for the upcoming season, tell me: Your (to provide exact equinox times) Your local climate (to predict foliage peaks)

If you prefer your seasons dictated by the tilt of the Earth and the position of the sun, you follow the astronomical calendar. This is the date most people recognize as the "official" start of fall.

Many birds begin their southward migration, while mammals gather food stores for hibernation.