Difference Between Equinox and Solstice


Main Difference

The main difference between Equinox and Solstice is that Equinox is longer and shorter nights during the year, whereas Solstice is the longer and shorter days during summer and winter.

Equinox vs. Solstice

The term equinox is derived from the Latin word means equal night. The term solstice is also derived from two Latin words “sol” and “sistere” word “sol,” meaning sun and “sistere,” meaning to stand. Equinox is the point which is at the closest distance from the equator. Solstice is the point of earth’s orbit around the sun and at a great distance from the equator. Equinox is related to the equal length of days and nights. Solstice is related to shorter days and longer days.


During equinox rotation of the earth is perpendicular to the sun. During the summer solstice, north poles of the earth are directed towards the sun while in winter solstice north poles of the earth directly away from the sun. The equinox happens two times each year. Solstice also happens two times in a year, once in summer and other in winter. The equinox happens at a specific period of time. The solstice happens for many days during the season.

Equinox is dealing with a specific period of time in day and night. During summer solstice in sunlight is longer, but during the winter solstice, the sunlight is shorter. In the course of an equinox, the sun spends equal time at the equatorial plane hence shows an equal length of day and night. In the case of solstice sun is away from the equatorial plane and changes the distance regarding the plane and hence shows the different length of days. Equinox depends on the spring and autumn season. Solstice depends on the summer and winter season.


Comparison Chart

The time of the year when the sun is near to the equator is the equinox.Time of the year when the sun is far from the equator is the solstice.
Refers To
Equal duration of day and nightLong and short day
At the start of spring and fall seasonDuring the start of summer and winter season
Occurs On
20th March and 22nd September21st June and 22nd December
Rotation of Earth
Rotation perpendicular to the sunNorth poles regarding the sun

What is Equinox?

During the equinox, it is noticed that area of earth or surface of earth shows the equal length of daylight and darkness that is 12 hours of daylight and 12 hours of darkness—equinox experiences in the spring season and autumn season. In the autumn season, the equinox is started about 21st September, and it is noted that at that time, equinox appears in the northern hemisphere. But in the spring equinox, which starts on 20th or 21st March and it appears in the southern hemisphere. This time or hemisphere may change from year to year.

It is also said that equinox is such a specific time of the year when a specific part of the earth is very close to the sun and at the position of the exact equator—everything from north to the south pole when aligned gets the same amount of sunlight. The equinox of the exact dates of September and March may change about three days each year. In the northern hemisphere, during the vernal equinox, day and night are equal in length at the start of spring. In autumn equinox day and night, both are equal in length at the start of autumn.

The term equinox is derived from the Latin word “aequincotium,” which is a combination of two words “aequus” means equal and “nox” or “notics” means night; hence the equinox means equal nights. The equinox refers to the instant of time at which the plane of earth and its equator pass directly through the sun’s central region.

What is Solstice?

The term solstice is derived from the Latin word “solstitium,” which means “sun-stopping.” During the solstice, sun reverses and stops its direction, and at the point of the horizon, the sun appears to be rise. At the time of the solstice, the period sun doesn’t appear in the sky for a longer time period because it doesn’t rise precisely instead of its rise to the north of east and sets to the north of the west.

In each year, solstice appears two times, once in the summer and the other in the winter. While solstice, the sun comes to the lowest point or highest point of the sky at noon and exhibits the longest days and shortest days of the year. Zenith of the sun is at its uttermost point of the equator during the solstice. On June solstice, the zenith of the sun reaches the northern hemisphere point of the northern hemisphere pole of earth and is directed towards the sun, making the angel of 23.40.

The seasons are getting reserved in the respective hemisphere, so that’s why winter solstice exhibits the shortest day of the year i.e., 21st December and summer solstice exhibits the longest day of the year i.e., 21st June. The term solstice is a wider term and is also used for the day when it occurs. On the day of the solstice, when the hemisphere gets the more sunlight, then it is said to be summer solstice; when the hemisphere gets the least sunlight, it is said to be the winter solstice.

Key Differences

  1. Equinox is a specific period during day or night, whereas solstice is related to the sunlight during summer or winter.
  2. An equinox occurs in March and September; on the other hand, the solstice occurs in June and December.
  3. Equinox deals with the equal length of day and night; conversely, solstice deals with the length of the day.
  4. An equinox happens for a specific moment of time; on the flip side, solstice that happens for the whole day.
  5. Equinox is about the specific time period during day or night, while solstice is about for the whole day.
  6. Equinox point is at a closet distance to the equator, although solstice point is at the largest distance from the equator.
  7. In an equinox, the earth shows perpendicular rotation as compared to the rotation of north poles of the earth in the solstice.
  8. Equinox is for a shorter period compared to the solstice, which is for them all day.
  9. Equinox appears twice in a year. However, solstice appears once in summer and once in the winter season.
  10. Equinox appears at the start of autumn and spring; on the other side, solstice appears during the whole summer and winter.


It is concluded that equinox is changed in day and night length, and solstice is the change in day length.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss