September 21
DAY OF THE YEAR
Historical anniversaries/September 21; 21 September; 21st September; September 21st; Sep 21; Sept 21; Sept. 21; 21 Sept; 9/21; 21/9; 21 Sep; 21st of September
It is occasionally the day of the autumnal equinox in the Northern Hemisphere and the day of the vernal equinox in the Southern Hemisphere, though this usually falls on September 22 or September 23.