The official beginning of autumn, the autumn equinox, occurs on Sunday, September 22nd.

What exactly happens during the equinox? Here is an overview:

THE AUTUMN EQUINOX:

According to NOAA, an equinox occurs when the Earth’s axis is neither tilted away from nor toward the sun.

This means that the sun is directly above the equator, so that day and night are approximately the same length at all latitudes.

DIFFERENCE BETWEEN AN EQUINOCTION AND A SOLSTICE:

There are only two times of the year when an equinox occurs: at the beginning of autumn (autumn time) and at the beginning of spring (spring time).

The beginning of the summer and winter seasons are marked by solstices. A solstice occurs when the Earth’s tilt (either toward or away from the Sun) is at its greatest.

>>>READ: A Tale of 2 Seasons: The Difference Between Meteorological and Astronomical Seasons

After the autumn equinox, the Northern Hemisphere begins to turn away from the Sun as the Earth continues its rotation until the winter solstice, which occurs on Saturday, December 21.

In terms of daylight hours, the winter solstice marks the shortest day of the year and the longest night. Conversely, the summer solstice marks the longest day of the year and the shortest night.

As daylight hours decrease in the fall, clocks will go back one hour on Sunday, November 3.

>>>READ: Where does daylight saving time come from? KSAT explains