What is an equinox?

What are equinoxes? What causes these astronomical events? Find out how they influence the seasons and hours of daylight on each planet. read more

An equinox is commonly regarded as the moment the plane of Earth's equator passes through the center of the Sun's disk, which occurs twice each year, around 20 March and 22-23 September. read more

Equinox definition, the time when the sun crosses the plane of the earth's equator, making night and day of approximately equal length all over the earth and occurring about March 21 (vernal equinox or spring equinox) and September 22 (autumnal equinox). read more

("Equinox" is derived from the Latin for "equal night.") After Sunday, the sun will shine more on the southern half of our planet and less on the northern half. Summer will be over in the Northern Hemisphere, and fall will have arrived. read more