Autumnal Equinox
September 22
The shortest day of the year in the southern hemisphere is the same day the the northern hemisphere has it's longest day, the Summer Solstice. Which occurs on either June 21 or 22.
Only near the North Pole, where the Sun goes round and round horizontally all day and all night, rising on March 21 and setting on September 22.
The day lengths in the southern hemisphere begin to increase between the Winter Solstice and the Vernal Equinox, same as in the Northern Hemisphere, but the time for the seasons is reversed. Winter solstice in the southern hemisphere falls on June 21 or 22 each year, and the vernal equinox is around 21 or 22 September.
During the portion that the Earth traverses during the periodfrom roughly March 21 until roughly September 22.
September 22
Nominally from June 21 until September 21 or 22, the northern hemisphere is in summer, whereas the southern hemisphere is in winter.
The equinox in autumn, on about September 22 in the northern hemisphere and March 20 in the southern hemisphere.
It occurs in March, currently on March 20 each year. (the same date is the "vernal equinox" in the Northern Hemisphere)
In the northern hemisphere August is in summer which lasts from 22 June through to 22 September
Ostara celebrates the Spring Equinox. In the northern hemisphere, it will be on March 20 and in the southern hemisphere it will be on September 22.
On March 20 for the Northern Hemisphere (this is the autumnal equinox in the Southern Hemisphere). The vernal equinox for the Southern Hemisphere will be either September 22 or 23.
From around 20 March to around 22 September, the sun is directly over the northern hemisphere. From around 22 September to around 20 March, the sun is directly over the southern hemisphere.
Northern Hemisphere: Fall - Autumn begins 2013 Sunday, September 22
The Autumnal equinox for the Northern Hemisphere officially begins on September 22, 2016.
Spring equinox occurs around March 20 and Fall equinox occurs around September 22 for the Northern Hemisphere. For the Southern Hemisphere these dates are opposite; the Spring equinox is around September 22 and the Fall equinox occurs around March 20.
In all parts of the world, in December and July occur soltices and in march and September, equinoxes.