You’ve heard of the “Harvest Moon.” Everyone has, but why? It’s just another full moon, one of 13 in 2023, so why is September’s full moon special?
Officially 100% full at 4:59 a.m. EDT on Friday, September 29, 2023—and best viewed as it appears on the eastern horizon at moonrise where you are later that day during dusk—the “Harvest Moon” truly is something special. Here’s why:
1. It’s Defined By The Equinox
The full moon that gets the “Harvest Moon” moniker is the full moon closest to the autumnal equinox, which in the northern hemisphere marks the end of summer and the beginning of autumn or fall. This year the equinox occurred at 06:50 UTC on Saturday, September. 23. The “Harvest Moon” will be full at 10:57 UTC on Friday, September 29.
2. This Year It’s Also A ‘Supermoon’
August’s second full moon—thus a “Blue Moon”—was 2023’s biggest and brightest “supermoon” simply because it was the closest full moon to Earth. That must happen every year because the moon orbits in a slight ellipse, so has a perigee and an apogee point each month. However, since technically a supermoon is declared when a full moon is within 90% of the moon’s closest approach to Earth, the “Harvest Moon” is 2023’s fourth and final supermoon. It won’t appear larger than usual, but its extra brightness may be noticeable.
3. It’s Traditionally Adored By Farmers
That slight extra brightness this year will be great to any farmers who need to get their crops in by hand—the reason why the “Harvest Moon” gets its name. Since a full moon shines all night long, September’s full moon is historically associated with harvesting crops late into the night. Mechanization has made that moot across most of the world, but the name has stuck.
4. It Will Light-Up The Sky For Several Nights
Whether or not there’s a supermoon, the “Harvest Moon’s” reputation for illumination is well deserved for other celestial reasons. On any given day of the year the moon rises about 50 minutes later than the previous day. However, in northerly latitudes of the northern hemisphere—such as Europe, where the name “Harvest Moon” originates—this full moon rises at a similar time for several nights close to the equinox. For example, in New York the moon rises at 18:35, 19:00 and 19:25 on September 28, 29 and 30, respectively. In London it’s 18:41, 18:54 and 19:08.
That happens because Earth’s tilt means the ecliptic (roughly the line in the sky that the moon orbits Earth along) makes a shallow angle with the horizon in the northern hemisphere, according to timeanddate.
It’s going to feel like there’s a full moon all week—and it explains why the “Harvest Moon” is, historically and culturally, such an important full moon that is easily noticed.
5. It’s Linked To Wine, Singing And Falling Leaves
September’s full moon is most famously known as the “Harvest Moon,” which according to Timeanddate is an Anglo-Saxon name, with Celtic and Old English names including “Wine Moon,” “Song Moon” and “Barley Moon.”
In North America it’s historically known as the Corn Moon—the dominant crop—though according to Farmer’s Almanac it’s also called the “Autumn Moon,” “Falling Leaves Moon,” “Leaves Turning Moon,” “Moon of Brown Leaves” and “Yellow Leaf Moon.” You get the idea.
6. Japan Celebrates It As ‘Tsukimi’
The Japanese tradition of observing the “Harvest Moon” is called Tsukimi, which translates as “looking at the moon.” However, the practice of observing September’s full moon—which occurs on the 15th day of the eighth month in the lunar calendar—goes back a thousand years, originating in China during the Tang Dynasty (618–907) according to Nippon.com.
From the 8th to the 12th centuries in Japan the elite staged moon-viewing parties including music and poetry. Nowadays Tsukimi is marked by people paying their respect to the moon and praying for a successful harvest. Every year the Tokyo Tower is specially lit up for the Tsukimi Harvest Moon Festival.
7. It Will Be Beneath The Night Sky’s ‘Great Square’
The “Harvest Moon” will be visible beneath the constellation the Pegasus, the horse, which is most obviously identified as its asterism the “Great Square.” It’s marked at each corner by four stars that are roughly similar in brightness. Rising in the eastern