As Earth revolves around the Sun, there are two moments each year when the Sun is exactly above the equator. These moments — called equinoxes — occur around March 20 or 21 and September 22 or 23. Equinox literally means “equal night,” since the length of day and night is nearly equal in all parts of the world during the equinoxes. A balance of light and dark that is both metaphoric and symbolic to those paying attention to change.
The March equinox marks when the Northern Hemisphere starts to tilt toward the sun, which means longer, sunnier days. In the Northern Hemisphere, the March equinox is called the vernal equinox, because it signals the beginning of spring (vernal means fresh or new like the spring). The September equinox is called the autumnal equinox, because it marks the first day of fall (autumn).
When the Northern Hemisphere starts to tilt toward the sun in spring, the Southern Hemisphere starts to tilt away from the sun, signaling the start of fall. Thus, in the Southern Hemisphere, the March equinox is called the autumnal equinox, and the September equinox is called the vernal equinox.
People have celebrated the vernal equinox for centuries. For ancient cultures, the vernal equinox signaled that their food supplies would soon return. Early Egyptians even built the Great Sphinx so that it points directly toward the rising Sun on the day of the vernal equinox.
Celebrating the beginning of spring may be among the oldest holidays in human culture. Occurring every year on March 20, 21, or 22, the spring equinox is the end of winter and beginning of spring. Biologically and culturally, it represents for northern climates the end of a dead season and the rebirth of life, as well as the importance of fertility and reproduction.
Ancient symbols were the hare (both because of its fertility and because ancient people saw a hare in the full moon) and the egg, which symbolized the growing possibility of new life, are still used in modern day celebrations at this time of year.