What is the Autumnal Equinox?

An autumnal equinox is when the day is just as long as the night and the days are getting shorter. This happens in late September for northern hemisphere and in late March for southern hemisphere. It...

It is one of the two times of year that the sun is over the equator. It happens around September 21/22 each year. Daylight and darkness are approximately equal.

There is an equinox in March and September. They are the time of the year when the tilt of the earth does not put either the northern or southern hemisphere tilted towards the sun. The Autumn equinox...

This question is unclear. Is the user asking for times, equinox dates for upcoming years, or a definition?

In 2011, the Autumnal Equinox begins on September 23rd.