September 2027 Moon Phases

September 2027 is the month summer hands off to autumn. There’s no eclipse or major meteor shower on the calendar this time, but the month still has its own signature event: the Full Corn Moon lands close enough to the autumnal equinox to also earn the Harvest Moon title this year, bringing with it one of the more interesting quirks of moonrise timing. Here’s what’s happening and when.

The Corn Moon doubles as this year’s Harvest Moon

September’s Full Moon is widely known as the Corn Moon, a name tied to the corn harvest ripening across much of North America around this time. “Harvest Moon” is a separate title, given each year to whichever Full Moon falls closest to the autumnal equinox — most years that’s September’s Corn Moon, but roughly one year in three it shifts to October’s Full Moon instead. This year, September 15 falls closer to the September 23 equinox than October’s Full Moon will, so the Corn Moon carries both names in 2027. For the fuller folklore and other traditional names for it, see our Corn Moon guide.

Why the Harvest Moon barely seems to move

Most nights, the Moon rises about 50 minutes later than it did the night before. Around the autumnal equinox, though, the Moon’s path meets the horizon at an unusually shallow angle in the Northern Hemisphere, so that nightly delay can shrink considerably — to roughly 25 to 35 minutes for several nights running at latitudes around 40°N to 60°N, though the exact figure varies quite a bit within that range depending on how far north you are. That means several evenings of bright, nearly full moonlight arriving relatively soon after sunset rather than progressively later, which historically provided extra evening light during the harvest season — hence the name. In 2027, this effect is centered on the September 23 equinox rather than the September 15 Full Moon date, so the nights to watch for the shortest moonrise gaps are the ones around the equinox. It’s easy to see for yourself: watch the Moon rise near sunset on several evenings around September 23 and compare how little the time shifts night to night.

The equinox arrives September 23

The autumnal equinox happens when the Sun crosses the celestial equator moving south, marking the astronomical start of autumn in the Northern Hemisphere. In 2027 that moment falls at 2:02 AM EDT on September 23 — nearly the same day as the month’s Last Quarter Moon — when day and night are approximately equal in length at many locations. From here through the December solstice, Northern Hemisphere days keep getting shorter and nights longer.