How the Moon Got Its Folk Names

Read any news story about a full moon and it will give the moon a name: the Wolf Moon in January, the Strawberry Moon in June, the Hunter's Moon in October. The names sound ancient. As a single tidy list, one name for each month, they are not.

NASA's account is short. The Maine Farmers' Almanac began publishing Native American names for full moons in the 1930s, and over time the names became widely known. The Old Farmer's Almanac, which keeps the best known version of the list today, describes its names as coming from Native American, Colonial American or other traditional North American sources. It is also candid about the exceptions: the Wolf Moon, it says, is not a traditional Native American name and is thought to have English origins, brought over by European settlers.

So the list on your phone's calendar is a twentieth century selection from older and more varied traditions. Different peoples named the moons differently, by their own seasons and work, and the almanac picked one name per month. That does not make the names less lovely. It makes them a piece of American folklore with a known publishing history, which is a story worth knowing.

Most of the names follow the calendar month. One follows the sky. The Old Farmer's Almanac defines the Harvest Moon as the full moon that occurs closest to the autumnal equinox, and notes that most years it falls in September and about every three years in October. When the Harvest Moon takes October's slot, September's full moon goes back to being the Corn Moon. The full moon after the Harvest Moon is the Hunter's Moon.

In 2027 the September equinox falls on September 23 at 06:01 UTC. The full moon of September 15 comes 7.3 days earlier, much closer than the October full moon three weeks after the equinox. So September 15 is the 2027 Harvest Moon, and October 15 is the Hunter's Moon.

Why would a harvest care about one full moon more than another? Because of when it rises. On an average night the Moon rises about 50 minutes later than the night before; in New York over all of 2027 the figure is 50.4 minutes. Around the September equinox, in the evening, the Moon's path through the stars meets the eastern horizon at a shallow angle. Each night it moves along that path, but it barely drops below the horizon, so it rises only a little later. In the Harvest Moon week of 2027 the delay in New York is 21 to 26 minutes. In London, further north, it is 12 to 15.

The almanac list is not the only time people tied the Moon to the turning year. In 725 the English monk Bede described the months of the early English calendar in The Reckoning of Time. They were lunar months, counted from the Moon, and their names said what the month was for.

Solmonath was named for the cakes offered to the gods. Weodmonath was the month of weeds, because there were so many of them. Blodmonath was the month of sacrifice, when livestock were offered. And Winterfilleth, the "winter full", took its name from a full moon: Bede explains that winter was counted from the first full moon of that month.

That last one is the closest older cousin of the Harvest Moon idea. A specific full moon, at a specific point in the year, marks a change of season. The thirteenth month those lunar calendars sometimes needed is the subject of Why 2027 Has 13 New Moons.

The same almanac is behind the best known lunar phrase of all. The Maine Farmers' Almanac used "Blue Moon" for a seasonal oddity: when a season holds four full moons instead of the usual three, the third of them is the Blue Moon. In 1946 the amateur astronomer James Hugh Pruett wrote in Sky & Telescope that seven times in 19 years there are 13 full moons in a year, and in explaining the almanac's term he misread its rule. His version, the second full moon in a calendar month, is the one most people use today. In 1999 Sky & Telescope itself traced the error, in an article by Donald Olson, Richard Tresch Fienberg and Roger Sinnott.

Both definitions still circulate, and 2027 shows the difference. No calendar month of 2027 holds two full moons, so there is no Blue Moon by Pruett's rule. By the almanac's own seasonal rule there is one. Spring 2027, from the March equinox on March 20 to the June solstice on June 21, holds four full moons: March 22, April 20, May 20 and June 19. The third, May 20, 2027, is a seasonal Blue Moon. The count of full moons in a year, and why 2027 has only twelve, is the subject of Why 2027 Has 13 New Moons.

Every name on the almanac list is a Northern Hemisphere name. A Strawberry Moon in June makes sense in New England; in Sydney or Buenos Aires June is the start of winter.

The Harvest Moon shows it best, because its rule is about the season, not the month. Apply the same rule to the southern autumn and the answer is the full moon nearest the March equinox. In 2027 that is March 22, 1.6 days after the equinox. The geometry flips with it. In the week around that full moon the Moon rises only 29 to 34 minutes later each night in Sydney, while in New York, where March is spring, the delay stretches to 70 to 77 minutes. Around the September full moon it is the other way round: 21 to 26 minutes in New York, 56 to 60 in Sydney.

So if you live south of the equator and a headline tells you tonight is the Harvest Moon in September, the sky is not wrong. The name was simply made for someone else's harvest.

The folk names are about seasons and work on the land. Astrology reads a full moon differently: by the sign the Moon is in, which is always the sign opposite the Sun. Astrologers treat each full moon as a peak of the lunar cycle that began at the new moon two weeks earlier, coloured by the two opposite signs involved.

The 2027 Harvest Moon, for example, falls at 22 degrees of Pisces, opposite the Sun in Virgo, the sign of the long Virgo stellium of late summer. The Hunter's Moon of October 15 falls at 21 degrees of Aries. Last year's Hunter's Moon, in Taurus, has its own guide: the full moon of October 2026. Every full moon of 2027, with its sign and time, is in the full moon calendar for 2027, and the 2026 version is here.

To see which house of your own chart each full moon lights up, cast your free birth chart; the Moon's sign in it is your Moon sign.