Harvest Moon to Rise this Weekend
Sky watchers and photographers will want to look up this weekend to see the Harvest Moon. The moon has been waxing larger each night, and full moon will occur the night of September 29 and 30. In traditional skylore, the Harvest Moon is the full moon closest to the autumnal equinox. For us in the Northern Hemisphere, the autumnal equinox came on September 22.
The Harvest Moon will begin to rise around 6:45 p.m. on Saturday, September 29. Officially, the crest of the full Harvest Moon will happen on at 10:19 p.m. CDT. On Sunday, the Harvest Moon will rise about 50 minutes later, around 7:20 p.m.
The moon will appear round and full on all the nights around this full moon. The Harvest Moon will be bright and full-looking for several nights. This procession of moonlit nights is what characterizes the Harvest Moon.
“Harvest Moon” is just a name for the full moon nearest the autumnal equinox. In the Northern Hemisphere, you’ll always see the Harvest Moon in either September or October. In the Southern Hemisphere, a moon with these same characteristics always comes in March or April.
Why is this the moon closest to the autumnal equinox called the Harvest Moon?
The shorter-than-usual time between moonrises around the full Harvest Moon means no long period of darkness between sunset and moonrise for days in succession. In the days before tractor lights, the Harvest Moon helped farmers to gather their crops, despite the diminishing daylight hours. As the sun’s light faded in the west, the moon would soon rise in the east to illuminate the fields throughout the night.
There’s also a name for the next full moon after the Harvest Moon. It’s called the Hunter’s Moon, and it comes this year on October 29.
On average, the moon rises about 50 minutes later each day. But when a full moon happens close to the autumnal equinox, the moon rises only about 30 minutes later daily for several days before and after the full Harvest moon. The reason for this is that the moon’s orbital path makes a narrow angle with the evening horizon around the time of the autumn equinox. The narrow angle of the ecliptic results in a shorter-than-usual rising time between successive moonrises around the full Harvest Moon.
These early evening moonrises are what make every Harvest Moon special. Every full moon rises around sunset. After the full Harvest Moon, you’ll see the moon ascending in the east relatively soon after sunset for several days in a row at northerly latitudes. Because of this, it seems as if there are several full moons, for several nights in a row, around the time of the Harvest Moon.