Wolf Moon, Harvest Moon: the traditional names of the full moons
Where full moon names come from: the series of American almanacs, the Harvest and Hunter's Moons, and the real history of the Supermoon and the Blue Moon.
Wolf Moon in January, Snow Moon in February, Worm Moon in March, all the way to the Cold Moon in December: the names of the full moons reappear every month in the news and on pages devoted to the sky. They are evocative names, partly old, but the complete series we know today has a more recent and less straightforward history than is often believed. Telling tradition apart from modern construction allows us to appreciate them better.
The most widespread series
The best-known list, of North American origin, assigns a moon to each month: Wolf in January, Snow in February, Worm in March, Pink in April, Flower in May, Strawberry in June, Buck in July, Sturgeon in August, Harvest or Corn in September, Hunter's in October, Beaver in November and Cold in December. The Pink Moon is not pink: the name recalls the spring flowering of a wild American plant, phlox.
This series was popularised in the twentieth century by American farmers' almanacs, which presented it as a collection of names used by the native peoples of North America and by European colonists. Some names do find a match in native traditions, but each people had its own system, tied to its language and environment, and a single list valid for all never existed.
The Harvest Moon and the Hunter's Moon
Two names have a precise astronomical basis and an older English tradition. The Harvest Moon is the full moon nearest the autumn equinox. At that time of year, at mid-northern latitudes, the full moon and those of the following days rise at short intervals from one another, because the ecliptic makes a small angle with the eastern horizon. For several evenings in a row there is therefore moonlight just after sunset, once useful for work in the fields.
The Hunter's Moon is the next full moon, usually in October, which shows the same phenomenon in a weaker form. The name is explained by the hunting season, when reaped fields made animals easier to see. Both names have been attested in English for centuries, well before complete monthly lists became popular.
Other names, other cultures
Every culture has given its own names to the moons, often linked to the months. In Anglo-Saxon England, as Bede reports, the months themselves were lunar and bore agricultural and religious names. In the Chinese calendar the full moon of the eighth month is at the heart of the Mid-Autumn Festival, while in India the full moon of each month takes the name of the month itself and many have their own festival, such as Guru Purnima in the month of Ashadha.
Modern terms such as Supermoon or Blue Moon should also be taken for what they are. Supermoon is a term coined in astrological circles at the end of the 1970s and later adopted by the media for a full moon near perigee. Blue Moon today means the second full moon in a calendar month, but this meaning stems from a misinterpretation published in an astronomy magazine in 1946.
The names of the full moons remain an evocative way of linking the sky to the months and seasons, and many of them preserve a real memory of farm work and hunting. Their history is nonetheless worth remembering: tradition is alive precisely because it changes, and recognising the recent additions takes nothing away from the charm of an autumn full moon rising red over the horizon.