The Harvest Moon is unlike any other full moon. But why is it special and what is the meaning behind the name?
In 2022, the Harvest Moon will first appear in the evening of Friday, September 9 before reaching peak illumination at 5:59 a.m. EDT on Saturday, September 10, according to the Farmers Almanac.
Technically, the moon only turns full at a specific point in time. At these times, the side of the moon that faces toward us is fully illuminated, appearing like a perfect circle.
But many people use the term full moon to refer to our natural satellite over the course of the whole night in which it reaches peak illumination. To most observers, the moon will appear full from September 9 to 11.
Full moons are a lunar phase that occur roughly once every month when the moon is located opposite the sun in space, with the Earth in between.
The term Harvest Moon is different from the other traditional full moon names, which are each associated with a specific month.
Instead, the name Harvest Moon is given to whichever full moon falls closest to the autumnal equinox—which this year arrives on September, 22.
As a result, the Harvest Moon can occur in September or October, depending on how the lunar cycle lines up with the Gregorian calendar.
The Harvest Moon most frequently occurs in September, in which case it replaces the Corn Moon. But on some occasions, it falls in October taking the place of the Hunter’s Moon.
The names given to full moons originate from a number of places and historical periods, including Native American, colonial American and European sources.
The name Harvest Moon likely originates from being an aide to farmers during the fall harvest season, according to the Almanac.
At this time of the year, the moon rises very soon after sunset, meaning there is bright moonlight early in the evening. This would have been beneficial to farmers in the days before artificial lighting.
Throughout the year, the moon rises an average of around 50 minutes later each day. But for the few nights around the Harvest Moon, this difference is smaller. Across the northern United States, for example, the moon rises only 25 to 30 minutes later each day at this time of year.
The September equinox marks the beginning of fall, in astronomical terms, in the Northern Hemisphere.
During the Northern Hemisphere’s fall equinox, the Earth’s axis, which is tilted at an angle of around 23.4 degrees relative to the plane of its orbit around the sun, is pointed neither towards nor away from the sun. At this time, the sun shines directly over Earth’s equator, and the length of day and night is roughly equal.