The Sun rises and sets exactly due east and due west on the equinoxes, and day and night are of equal length. So, the solstices and equinoxes are important calendar points that come to us from the apparent position of the Sun in our sky.

The term equinox, like solstice, finds its origin in Latin with the roots aequus meaning “Equal” and nox meaning “Night.” Astronomers define the equinox as the moment the Earth’s Equator on its axis passes the same plane of the Sun’s equator, but its name reveals more of what we experience of these March and September …

What they do have in common, however, is serving as markers of the transition points between the seasons. Essentially, the solstices mark the points at which the Earth is tilted toward the Sun at its most extreme angles, and the equinoxes mark the neutral transition points between these two extremes.

There also would be no need to mark equinoxes or solstices. The two solstices happen in June (20 or 21) and December (21 or 22). These are the days when the Sun’s path in the sky is the farthest north or south from the Equator. The equinoxes happen in March (about March 21) and September (about September 23).

What are solstices and equinoxes? When the sun is furthest north or south from the equator, it’s a solstice. When neither hemisphere is tilted toward or away from the sun, it’s an equinox. They are related to the seasons because it makes the days longer or shorter, warmer or colder.

There are only two times of the year when the Earth’s axis is tilted neither toward nor away from the sun, resulting in a “nearly” equal amount of daylight and darkness at all latitudes. These events are referred to as Equinoxes. The word equinox is derived from two Latin words – aequus (equal) and nox (night).

Explanation: The equinoxes signify a change in the seasons. The equinoxes are the main circumstances when the sun based eliminator is opposite to the equator. Therefore, the northern and southern halves of the globe are similarly enlightened.

Solstices occur because Earth’s axis of rotation is tilted about 23.4 degrees relative to Earth’s orbit around the sun. This tilt drives our planet’s seasons, as the Northern and Southern Hemispheres get unequal amounts of sunlight over the course of a year.

Every six months, once in March and again in September, an equinox splits Earth’s day almost in half, giving us about 12 hours of daylight and 12 of night.

The March equinox – also called the vernal equinox – marks the beginning of the spring season in the Northern Hemisphere and the autumn season in the Southern Hemisphere.

What is an equinox? At two points in the year the Sun will illuminate the northern and southern hemispheres equally. These are known as the equinoxes: the autumnal equinox and vernal or spring equinox.

Vernal equinox, two moments in the year when the Sun is exactly above the Equator and day and night are of equal length; also, either of the two points in the sky where the ecliptic (the Sun’s annual pathway) and the celestial equator intersect.

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).

In the northern hemisphere, the spring, or vernal equinox happens around March 21, when the sun moves north across the celestial equator. The autumnal equinox occurs around September 22nd, when the sun crosses the celestial equator going south.

The first day of spring is determined by the vernal equinox, which is when the sun crosses over plane of the earth’s equator, making night and day approximately equal lengths all over the world. One the day of the equinox passes, both of Earth’s hemispheres get an equal amount of sunlight.