The two days are known as the Equinox. The spring Equinox (typically June 21) is known as the "Vernal Equinox". The fall Equinox (Typically September 21) is known as the "Autumnal Equinox".
The vernal equinox is also known as the spring equinox.
The autumnal equinox is also known as the fall equinox and the September equinox. An example of a sentence using "autumnal equinox" is "This year's autumnal equinox falls on a full moon. "
The Vernal Equinox
March Equinox or also known as Vernal Equinox or Spring Equinox.
"Vernal" is Latin for "spring".
the autumnal equinox
It is called an equinox. In the spring it is known as the Vernal Equinox while in the autumn it is known as the Autumnal Equinox. Both take place around the 21st of March/September, but the date varies slightly each year.
The Sun is directly overhead the equator two times per year, known as the Equinoxes. In the northern hemisphere, the Spring Equinox occurs on March 20 and the Fall Equinox occurs on September 22.
equinox
The Vernal Equinox, also known as the Spring Equinox, occurs once per year and is the kick off to the season of Spring. It is when the sun's rays are directly beaming down on the Tropic of Cancer. No city can be located on the Vernal Equinox, as it is not a place. However, a city could be placed at the Tropic of Cancer in which the Vernal Equinox happens, although no city is currently located on this line of latitude.
Once. In Autumn (stangely). Known as 'Fall' in the colonies.