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Autumnal Equinox – Fall Equinox

Equinoxes are opposite on either side of the equator, so the autumnal (fall) equinox in the Northern Hemisphere is the spring (vernal) equinox in the Southern Hemisphere and vice versa.

Equinox and solstice illustration
Equinoxes and solstices happen twice a year.
Equinoxes and solstices mark the start of astronomical seasons. The equinoxes start spring and fall, while solstices start astronomical summer and winter.

When is the Equinox in my city?

Autumnal (Fall) Equinox, Northern Hemisphere:

(USA & Central America, Asia, Canada, Europe, Northern Africa)

September equinox 2015:
September 23, at 08:20 UTC

Autumnal Equinox, Southern Hemisphere

(Australia, New Zealand, South America, Southern Africa)

March Equinox 2016:
March 20, at 04:30 UTC

Not entirely equal day & night

On the two equinoxes every year the sun shines directly on the equator and the length of day and night is nearly equal – but not exactly.

Equinox the first day of fall?

In the northern hemisphere, the fall equinox marks the first day of fall (autumn) in what we call astronomical seasons. There's also another, more common definition of when the seasons start, namely meteorological definitions, which are based on average temperatures rather that astronomical events.

Topics: Astronomy, Sun, Earth, Seasons, September, March

In this Article

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Equinox & Solstice

  1. Nearly Equal Night & Day
  2. March Equinox
  3. 10 Facts: March Equinox
  4. Vernal (Spring) Equinox
  5. Customs Around March Equinox
  6. September Equinox
  7. Autumnal (Fall) Equinox
  8. Customs: September Equinox
  9. June Solstice
  10. Customs Around June Solstice
  11. Summer Solstice
  12. December Solstice
  13. Winter Solstice

Equinox & Solstice Worldwide


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