What Does Equinox Mean?

Dates

• In most instances, the equinoxes occur on March 21 or March 22 for the vernal equinox in the Northern Hemisphere, and on Sept. 21 or Sept. 22 for the autumnal equinox in the Northern Hemisphere. Rather than being an entire day, the equinox actually occurs at an exact moment.

Sun

• The moment when the equinox occurs is the moment when the sun's center is exactly above the Earth's equator. On the day the equinox occurs, the sun spends almost exactly half of the 24-hour period above the planet's horizon and the other 12 hours below the earth's horizon.

Leap Year

• Leap year keeps the date of the equinoxes close to the same each year. Because the equinox falls about a quarter of a day later each year, the date would shift a full day every four years if not for the leap year shift.

Observances

• Many cultures celebrate the beginning of a new year on the day of one of the annual equinoxes. The Jewish Passover and the Christian observance of Easter are calculated according to the date of the equinox. Several other religious observances and cultural festivals are marked by these occasions.

Folklore

• Over centuries and decades many legends and folk traditions have been connected with the equinox. One states that an egg can be balanced on its end at the time of the equinox. Another states that objects may move on their own on these dates when the day and night are in balance.