- The harvest moon is the full moon closest to the fall equinox.
- September is generally the month associated with harvest moons.
- When the moon rises, the moon is often reddened by clouds and dust in our atmosphere.
Prepare for a late summer show: A beautiful “harvest” full moon will rise in the eastern sky on Monday evening, September 20, which will reach its peak illumination at 7:54 p.m. EDT.
The harvest moon is the full moon closest to the fall equinox, which this year will be on September 22.
Why the moon nickname “harvest”? “Before tractors with lights, it was crucial to have moonlight to work quickly before the rain made it rot,” said Alan MacRobert, editor of Sky & Telescope magazine.
Many crops ripen at the same time in late summer and early fall, so farmers found themselves extremely busy this time of year, according to NASA. They had to work after sunset.
For several evenings, moonrise occurs shortly after sunset, according to the Old Farmer’s Almanac. “This translates into an abundance of bright moonlight early in the evening, which was a traditional aid to farmers and crews harvesting their summer crops. That’s why it’s called the ‘harvest moon’! “
The Farmer’s Almanac adds that since the fall equinox can occur from September 22 to 23, it means that the harvest moon can arrive as early in the calendar as September 8 or as late as October 7.
So a summer harvest moon, especially one that occurs just days before the equinox, is not really such a rare event, the Almanac said. “In fact, about 50% of all harvest moons occur during the summer.”
September is generally the month associated with harvest moons; they occur almost 76% of the time, while October harvest moons occur on average just 24%, the Almanac said.
In addition, at moonrise, the moon is often reddened by clouds and dust in our atmosphere. Moons close to the horizon are also inflated to an inordinate size by the illusion of the moon, a well-known but still mysterious eye trick that makes low moons appear much larger than they actually are. .
For a real blast from the past, check out this: The Harvest Moon was the subject of this catchy pop standard from the early 1930s: