September 22nd
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.
fall equinox partial equinox
The first day of spring is determined by the vernal equinox, which occurs around March 20th in the Northern Hemisphere. This is when day and night are approximately equal in length, and it marks the beginning of spring.
Autumnal Equinox was 23. September in 1978
The Spring and Fall Equinoxes are the first days of Spring and Fall. In the southern hemisphere, this is not the case. The Spring equinox occurs around the 21st or 22nd of September, not the first day of Spring, which is September 1. The Autumn equinox occurs around the 21st or 22nd of March, not the first day of Autumn, which is March 1.
In North America, the first day of fall is considered to be on September's equinox. Every year, there is another equinox around March 20.
Sept. 22
That is the Vernal Equinox; as opposed to the first day of Fall's Autumnal Equinox.
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.
The equinox is the only day of 12 hours of night and day. It Occurs every spring and fall.
The northern hemisphere has two seasons at a time. In the northwest, the official first day of fall is September 21st. In the northeast, the official first day of fall is June 21st. Technically, though, if you looked at the real symptoms of fall, the first days of fall would be October 24th in the northwest and May 24th in the northeast.
the autumnal equinox
The adjectives vernal and autumnal mean "of spring" and "of autumn (fall)" respectively. The equinox, when the day and night are even, occurs twice a year. Once in spring and once in autumn (fall) as we move from the extremes of the summer and winter solstices. Therefore we have a vernal equinox (in spring) and an autumnal equinox (in autumn/fall).
In the Spring and Fall equinox, night and day have the same number of hours. Equi = equal.
The answer is autumnal equinox.
The Fall Equinox of 2014 is on Tuesday, September 23. It will be at 10:29 PM Eastern Standard Time. This is when the day and night are equal.
The longest day and shortest night occurs on the summer solstice. The shortest day and longest night occurs on the winter solstice. Midway between these points (2x a year) are the equinox, where the day and night are of equal length.