Definitions by Wil Mundy

vernal equinox

The moment at which the Sun passes over the equator, occurring around March 21, marking the beginning of Spring.

The only times that the amount of daylight and night are equal is during either the Autumnal or Vernal Equinox.

vernal equinox by Wil Mundy January 27, 2008

Autumnal Equinox 

The moment at which the Sun passes over the equator, occurring around September 21st or 22nd, marking the beginning of Autumn or Fall.

The only times that the amount of daylight and night are equal is during either the Vernal or Autumnal Equinox.

Autumnal Equinox by Wil Mundy January 27, 2008