Farm Collector Blogs > Looking Back

Blue Moon

by Sam Moore

Tags: moon phases, blue moon, New Year's Eve,

Sam Moore  
Sam Moore   

“Blue moon, you saw me standing alone, without a dream in my heart, without a love of my own.”

— “Blue Moon,” Richard Rodgers and Lorenz Hart, 1934

I’m writing this on New Year’s Eve and, although it’s overcast outside and I can’t see it, there’s what is commonly called a “blue moon” overhead.

When I was a kid, folks often used the expression “once in a blue moon” or “never in a blue moon” to describe something that occurred very rarely, or that might never happen at all. I didn’t know what the term referred to since I’d never actually seen a blue moon; every moon looked yellow or white or maybe gray to me.

There have been several occasions when the moon actually did look as though it was blue, mainly due to dust, smoke or ashes from some cataclysmic event on earth permeating the atmosphere. One such event occurred in 1883, when the Indonesian volcano Krakatoa erupted, spewing so much ash into the atmosphere that moonbeams passing through the clouds of ash appeared blue or green for several years after.

A full moon occurs every 29 days, so it’s possible for there to be two in a single month, although it is relatively rare, happening on an average of once every 2.7 years. In 2009 there was a full moon on Dec. 2 and another on the 31st.

The common perception today is that a second full moon appearing in any single month is a blue moon. However, the Maine Farmers’ Almanac (first published in 1818) interprets a blue moon as being the third full moon of four in any one season – spring, summer, fall or winter – always occurring between the 20th and 23rd of the months of May, February, August or November, and almost exactly one month prior to the vernal equinox (about March 21), the autumnal equinox (about Sept. 22), the summer solstice (about June 21) and the winter solstice (Dec. 21). 

Accordingly, the last true blue moon was on May 19, 2008, being the third full moon of the four between the vernal equinox on March 20 and the summer solstice on June 20. Full moons that spring occurred on March 21, April 20, May 19 and June 18. As can be seen, none of those months had two full moons, although the spring season itself had four. The next blue moon will be on Nov. 21, 2010, that being the third full moon of the four occurring between the autumnal equinox on Sept. 23 (also the date of the first full moon), and the winter solstice on Dec. 21. Dec. 21, 2010, is the date of the fourth full moon of the season, which will go through a total eclipse on that night as well.

The original need to identify a blue moon arose centuries ago in Europe from the need to calculate the exact date of Easter on the Christian ecclesiastical calendar. The normal year had 12 full moons and each of these had a name. According to Biblical clues, Easter must fall on the fourteenth day of the Paschal Moon, which corresponds to the vernal equinox. A thirteenth full moon in any given year had no name and threw off these calculations, so the blue moon was dreamed up to keep things on track.

American Indians put great store in the phases of the moon, using moons instead of months to mark the passing of time. The most common names for the full moons among these people were as follows:

January: Wolf Moon, in reference to the hungry howling of wolves around the camps.

February: Snow Moon, because across northeastern America, the heaviest snows fell in that month. Some tribes used the name Hunger Moon, because food was scarce at that time.

March: Worm Moon. As the ground warmed, earthworms appeared. European settlers called this the Lenten Moon.

April: Pink Moon, after a spring wildflower. Sometimes known as Sprouting Grass Moon.

May: Flower Moon, because of the many wildflowers that bloomed in great profusion in May. Also called Corn Planting Moon, as that was the time to plant corn or maize.

June: Strawberry Moon. The sweet, red strawberries ripened during that month.

July: Buck Moon. Buck deer sprout new antlers at that time. Also known as the Hay Moon because grass was cut at that time.

August: Sturgeon Moon, from the huge spawning runs of these fish when they were very easy to catch. Sometimes called Green Corn Moon or Grain Moon as well.

September: Harvest Moon or Corn Moon, recognizing the time when American Indians harvested corn, pumpkins, squash, beans and other staples.

October: Hunter’s Moon. The month when summer-fattened game was taken and stored for the long winter ahead.

November: Beaver Moon or Frosty Moon. Time to set beaver traps before ponds froze.

December: Cold Moon or Long Nights Moon, for obvious reasons. European settlers called it the Moon before Yule.

Farmers used to plant and harvest crops, butcher animals and do many other chores according to the phases of the moon. For example, potatoes were always planted during the “dark of the moon,” and nothing was ever planted on the day of a full moon or a new moon. The rules for farming by the moon are too numerous and complex to squeeze into this article. Maybe someday.