September’s full Harvest Moon reaches its peak on Monday, September 20, 2021. Learn how the Harvest Moon got its name—plus, see Moon phase dates, Best Days by the Moon, folklore, and more!
When to See the Full Moon in September 2021
This year, look for September’s full Harvest Moon to rise in the southeast just after sunset on Monday, September 20—just two days before the fall equinox! This full Moon reaches peak illumination at 7:54 P.M. Eastern Time on the 20th.
Why Is It Called the Harvest Moon?
The full Moon names used by The Old Farmer’s Almanac come from a number of places, including Native American, Colonial American, and European sources. Traditionally, each full Moon name was applied to the entire lunar month in which it occurred and through all of the Moon’s phases—not only the full Moon. The Harvest Moon, however, is a bit different!
The Harvest Moon
The full Moon that happens nearest to the fall equinox (September 22 or 23) always takes on the name “Harvest Moon.” Unlike other full Moons, this full Moon rises at nearly the same time—around sunset—for several evenings in a row, giving farmers several extra evenings of moonlight and allowing them to finish their harvests before the frosts of fall arrive. Read more about the Harvest Moon!
While September’s full Moon is usually known as the Harvest Moon, if October’s full Moon happens to occur closer to the equinox than September’s, it takes on the name “Harvest Moon” instead. In this case, September’s full Moon is referred to as the Corn Moon.
The Corn Moon
This time of year—late summer into early fall—corresponds with the time of harvesting corn in much of the northern United States. For this reason, a number of Native American peoples traditionally used some variation of the name “Corn Moon” to refer to the Moon of either August or September. Examples include Corn Maker Moon (Western Abenaki) and Corn Harvest Moon (Dakota).
Alternative September Moon Names
Other Moon names for this month highlight how September is the transitional period between summer and fall:
- Autumn Moon (Cree)
- Falling Leaves Moon (Ojibwe)
- Leaves Turning Moon (Anishinaabe)
- Moon of Brown Leaves (Lakota)
- Yellow Leaf Moon (Assiniboine)
The behavior of animals is also a common theme, with Child Moon (Tlingit) referring to the time when young animals are weaned, and Mating Moon and Rutting Moon (both Cree) describing the time of year when certain animals, like moose, elk, and deer, are looking to mate.
Moon Phases for September 2021
Here are Moon phase dates and times (EDT) for the month of September. Check our Moon Phase Calendar for dates and times in your city.
|New Moon: September 6, 8:52 P.M. EDT|
|First Quarter: September 13, 4:41 P.M. EDT|
|Full Moon: September 20, 7:54 P.M. EDT|
|Last Quarter: September 28, 9:58 P.M. EDT|
When is the next full Moon? Consult our Full Moon Calendar to find out.
September Full Moon Video
Why does the Moon ride high or low in the sky? Find out the answer to this question—and learn more about September’s Full Moon—in this entertaining video.
Photo Credit: Almanac reader, Robin Osbon
Best Days in September 2021
Below are the best days for activities, based on the Moon’s sign and phase in September.
|Harvesting aboveground crops||14, 15|
|Harvesting belowground crops||23–25|
|Canning and Pickling||1, 2, 28–30|
Moon Facts & Folklore
- Usually, the Moon rises about 50 minutes later each day, but around the time of the autumnal equinox, it rises only around 30 minutes later in the United States—even less in Canada.
- Frost occurring in the dark of the moon kills fruit buds and blossoms, but frost in the light of the moon will not.
Are you a full Moon lover? Share your thoughts below!