This weekend – beginning Friday evening, and definitely Saturday and Sunday, October 12 and 13, 2019 – the moon will look full, or nearly so, to the eye. October’s full moon is the Northern Hemisphere’s first full moon of autumn, and the Southern Hemisphere’s first full moon of spring. Last month’s full moon was the closest full moon to the autumn equinox. By the decree of skylore, it was the Harvest Moon. The full moon immediately following the Harvest Moon is – again, according to skylore – the Hunter’s Moon.
What is a Hunter’s Moon? Is it just a name? In fact, the Hunter’s Moon – like the Harvest Moon – has special characteristics. If you watch where the moon rises along your eastern horizon for the next several days, from either the Northern or Southern Hemisphere, you’ll see the moon rising farther north (left) on the horizon each day.
At northerly latitudes, that means a minimal lag time between successive moonnrises. The moon usually rises about 50 minutes later each day. Around the time of the Harvest and Hunter’s full moons, it rises at or near sunset for several nights in a row, with no long period of darkness between sunset and moonrise. There’s a grand procession of moonlit nights in this season of waning daylight, here in the Northern Hemisphere. Many notice it – have always noticed it – and that’s why the Harvest and Hunter’s Moons are so well known.
At southerly latitudes, things happen in the opposite way. The ecliptic – or path of the sun, moon, and planets – makes a steep angle now to the evening horizon, as seen from Southern Hemisphere locations. That means the time between successive moonrises will be particularly long this weekend, as seen from the Southern Hemisphere.
Astronomers define a full moon as happening at a well-defined instant, when the moon is 180 degrees opposite the sun in ecliptic longitude. That moment happens on Sunday, October 13, 2019, at 21:08 Universal Time (UTC).
Want to know when the moon turns full in your time zone? Visit Sunrise Sunset Calendars and check the moon phases box.
Want more specifics on moonrise times? Any full moon rises at or near sunset, and then rises – on the average – 50 minutes later the following day. But, at 40 degrees north latitude, the moon now rises some 25 to 30 minutes later (instead of the average 50 minutes later), and will continue to do so for the next several days. At higher latitudes, the Hunter’s Moon effect is even more pronounced. At Fairbanks, Alaska (65 degrees north latitude), the moon rises at nearly the same time for days on end, centered around this weekend’s full moon.
Want more about the Harvest Moon? Depending on time zone, last month’s full moon took place on Friday, September 13, or Saturday, September 14. Read more: Harvest Moon on Friday the 13th
What else should you watch for? If you’re outside watching for the moonrise, also notice Earth’s shadow ascending in the east.
Before the advent of artificial lighting, our ancestors relied on moonlight for nocturnal activities. That’s why they so valued the full moon, which rises in the east around sunset, climbs highest in the sky around midnight, and sets in the west around sunrise. Our ancestors at mid-northern and far-northern latitudes surely noted the peculiar rising times of September and October full moons, when the moon rises near sunset for several evenings in a row. In September, the story goes, they used those moonlit evenings to continue working in the fields, bringing in the crops. Hence the name Harvest Moon. In October (or November), they used the light of the full moon – rising so soon around the time of sunset – to hunt for game that might be scooting along over the harvested fields. Hence the name Hunter’s Moon.
Enjoy the October full moon, the Northern Hemisphere’s Hunter’s Moon and the Southern Hemisphere’s first full moon of spring!
Bottom line: The grand procession of moonlit nights in the season of waning daylight remains the legacy of the Harvest and Hunter’s Moons. In 2019, watch for the full, or nearly full moon, around October 11, 12, 13 and maybe even 14. Have fun!
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.