If you took an evening walk or happened to look out your window eastward last Thursday, you saw what some call the Worm Moon, a term American Indians introduced. While these nomadic people didn’t follow a Julian calendar, they knew the importance of using seasonal lunar phases to record passing time.
In certain climate zones, snow had melted enough to reveal visible earthworm casts, indicating returning robins. Thus the March moon became Worm Moon. Northern tribes might call that same orb Full Crow Moon due to cawing of returning crows or Full Crust Moon due to crusts topping snow from spring melts and freezes. Eastern tribes sometimes called it Sap Moon because of rising maple sap. This practice of using regional descriptions to name monthly full moons makes each one unique.
It seems calling the moon something specific like Snow Moon (February), Thunder Moon (July), or Long Nights Moon (December) made humans more aware of passing seasons. Living a migratory life in tipis or other portable housing had to make it easier recognize these cycles and their natural connections.
Although I live in a traditional house, moving from city lights to a rural area introduced me to these monthly phases. Growing up in a city saturated by light clutter, I had no understanding of waning and waxing or even full moons until I discovered going to the beach under a June full orb to capture silvery grunion laying eggs on shore. Until then, I hadn’t noticed most calendars include moon cycles for the light-clutter impaired.
As an adult living in Kansas and driving home from late practices and games, I eventually noticed predictable moon cycles. After several months, I realized the moon waxed or grew into a full moon from the left, or in a D-shape. Shrinking or waning moons disappear from the right in a C-shape. Despite studying these phases using ping pong balls in a grade school science class, it took seeing that butter-colored satellite go through its nightly paces in rural skies to understand what my teacher tried to show me year earlier.
As I grew more attuned to moon phases, I noticed we sometimes have two moons in a month. I learned his happens about every 33 months because moon cycles are about 29 and half days. In recent decades, this second full moon in a month has been called a blue moon, hence the saying “once in a blue moon” to mean something that doesn’t happen very often. Even rarer are two blue moons in one year, which must occur on either side of February since it only has 28 days. For those of us who love full moons, wait for a summer blue moon. Mark the calendar and plan a memorable moonlight picnic or campout.
Over time, the visible moon will shrink to nothing, leaving us with a new or dark moon. Then we can watch it grow into either an April moon if we’re tied to the Julian calendar or to a Grass Moon if we prefer to think seasonal change drives the full moon’s name.