September Equinox: Shifting Light

Quick Facts

  • Summary: a celebration of the autumnal equinox in the Northern Hemisphere and the vernal equinox in the Southern Hemisphere
  • 2019 Date: 23rd September (exact timing depends on location)
  • Celebrated by: Numerous cultures worldwide, modern pagans
  • Linked Holidays: March Equinox, Wiccan Wheel of the Year festivals, Harvest Festival

Background and Theological Significance

The September Equinox is the equinox that occurs each year between 21st and 24th September according to the Gregorian calendar. The word ‘equinox’ comes from the Latin words ‘aequus nox’ meaning ‘equal night’ and refers to the moment when the plane of the Earth’s equator directly faces the sun. Due to the axis of the Earth’s rotation, the sun directly faces the equator twice during each complete orbit, meaning that there are two equinoxes every year. During an equinox the Northern and Southern Hemispheres will be equally illuminated by the sun, and the length of day-time and night-time will be approximately equal. The September Equinox refers to the equinox that occurs when the sun is on its southward journey across the face of the Earth. In the Northern Hemisphere this is often called the autumnal equinox because it marks the start of autumn and the approach of winter. In the Southern Hemisphere it is often called the vernal equinox because it marks the start of spring and the approach of summer. The polar opposite of the September Equinox is the March Equinox, which occurs during the sun’s northward journey and marks spring in the Northern Hemisphere and autumn in the Southern Hemisphere.

The September Equinox has traditionally been regarded as an important marker of the seasons, along with the March Equinox and the June and December Solstices. It has been celebrated as an important festival in many different cultures worldwide, and very often takes the form of a harvest festival in the Northern Hemisphere. It has historically been a particularly important observance for pagans and remains a fixture in the calendar for many contemporary pagans.


The vernal and autumnal equinoxes have been observed as important phenomenon by human societies for thousands of years, usually relating to the end of the summer and the approach of winter or vice versa. In ancient Greece, the abduction of Persephone (a goddess of spring) by Hades (the god of the dead) and her descent to the underworld was associated with the autumnal equinox due to the belief that spring did not arrive until she had returned to the world above. Similar to the summer and winter solstices, it is possible that certain ancient monuments were constructed with the equinoxes in mind. For instance, the great pyramid of El Castillo in Chichen Itza in Mexico is built in such a way that the sunlight on either one of the equinoxes causes a series of shadows that look like a writhing serpent. Whether the pyramid was built with this in mind is unclear, but it is likely to have held great significance due to the Maya veneration of the snake god Kukulkan.

In northern Europe, the autumnal equinox roughly coincides with the final harvest of the agricultural year. The word ‘harvest’ actually derives from the Old English ‘haerfest’ meaning ‘autumn’. The Harvest Moon is the full moon nearest to the autumnal equinox, and the traditional Harvest Festival is held on the nearest Sunday. The Harvest Festival in Europe is of pagan origin but has been an important feature in the Christian year for many centuries and is nowadays usually celebrated as a thanksgiving service in church for the bounty of the harvest.

The September Equinox has been reclaimed by many modern pagans as a sacred date in the annual cycle of nature, including followers of Wicca who observe it as one of the eight major festivals in the Wheel of the Year. In the Northern Hemisphere, the autumnal equinox has been named Mabon after a Welsh deity, although there is little evidence that Mabon was venerated on this festival earlier than the 1970s. In the Southern Hemisphere, where the September equinox is the vernal equinox, it is celebrated as Ostara in honour of the Germanic goddess Ēostre. Both are important occasions to celebrate the changes in the year and to give thanks for the life-sustaining fertility of nature.

What Happens?

Due to slight discrepancies between the tropical year and the Gregorian calendar (which not even a leap year fully accounts for), the exact date and time of the September Equinox will change each year. However, it will always fall between 21st and 24th September.

The most prominent association with the September Equinox in the Northern Hemisphere is with the end of the harvest. Harvest festivals abound on or near the equinox, including the Mid-Autumn Festival in China and Vietnam which is celebrated on the 15th day of the 8th month of the lunar calendar. As this is always a full moon day, it is traditional to celebrate by baking and eating special mooncakes. The Harvest Festival in northern Europe is also a time to give thanks for the harvest and is a merger of both pagan and Christian traditions.

Other festivals from various cultures include Higan, which is celebrated by Japanese Buddhists on both of the equinoxes, and Mehregan, a Zoroastrian festival of the autumn. The September Equinox is also of particular importance to modern pagans in both the Northern and Southern Hemispheres, who consider it a time to celebrate the peaceful rhythm of the natural world. The importance of the September Equinox to many different cultures and religious traditions demonstrates the profound link between human spirituality and the world in which we live.

Sunset at the Autumn Equinox‘ by Sylvia Duckworth is licensed under CC by SA 2.0