The Harvest Moon and Hunter’s Moon are the traditional names for the Full Moons occurring in autumn, usually in September and October, respectively. These two names go back to the early 18th century.
The Harvest Moon is the Full Moon closest to autumnal equinox. This year it became full in the early morning today, September 25, 2018. The Hunter’s Moon is the Full Moon that follows the next month.
Coincidentally, or apocryphally, some Native Americans also referred to this Full Moon as a hunting moon. Indian tribes of eastern and northern North America had as diet staples corn, pumpkins, squash, beans, and wild rice, and of which would normally be ready by this Full Moon. The Corn Moon was another Native American name for this Full Moon.
In 2010, the Harvest Moon occurred on the night of the equinox itself for the first time since 1991. Most years, the Harvest Moon is in September though it can be in October.
There are other names for autumn Full Moons: Nut Moon, Mulberry Moon, Gypsy Moon, Singing Moon, Barley Moon, Barley Moon, Elk Call Moon and Fruit Moon.
I know that many people think of the Harvest and Hunter Moons as being more orange-tinged. That fits in nicely with autumn tree colors and Halloween decorations, but really the Moon will not appear any more orange or red this season than it will during the year when there is enough atmosphere/pollution to add some color to our view. Also, the tilt of the Earth after the equinox gives a warmer color of the moon shortly after it rises. But it is an optical illusion. When the Moon is low in the sky, we are looking at it through more atmospheric particles (including pollution) than when the moon is overhead. All of that scatters the blue light but allows the reddish component of the light to travel a straighter path to your eyes.
And that low hanging Moon, to our eyes, is also perceived as being larger than one that is high in the sky. This is known as a Moon Illusion.
The Full Moons of September, October and November as seen from the northern hemisphere correspond to the full moons of March, April and May as seen from the southern hemisphere.