The Pink Moon is the common name assigned to the full moon that occurs during April. This designation is one of a series of traditional names given to each month’s full moon, rooted in cultural traditions that tracked the changing seasons.
Identifying the Annual Timing
The Pink Moon is not fixed to a single calendar date but appears annually as the full moon phase that falls in April. The moon’s cycle, which takes approximately 29.5 days to complete, causes the date of the full moon to shift slightly each year.
Its appearance is always tied to the lunar cycle. It is frequently the first full moon after the spring equinox in the Northern Hemisphere. This placement sometimes makes the Pink Moon the Paschal Full Moon, which is used to calculate the date of Easter Sunday. Observers can predict the precise moment it reaches 100% illumination.
The Truth About Its Appearance
Despite its evocative name, the Pink Moon does not display a pink hue in the night sky. The moon’s natural color is a neutral gray, and the light that reaches Earth is simply reflected sunlight. In the absence of atmospheric interference, the full moon appears bright white or a pale yellow-white.
Any color deviations seen are the result of physics and Earth’s atmosphere, not the moon itself. When the moon is low on the horizon, its light must travel through a greater portion of the atmosphere to reach an observer. This process, known as atmospheric scattering, causes shorter wavelengths of light, such as blue and violet, to be filtered out.
The longer, less-scattered wavelengths of light—red, orange, and yellow—successfully penetrate the dense air near the horizon. This effect causes the moon to sometimes appear golden, deep orange, or a pale amber when it rises or sets. Factors like dust, pollution, or haze can intensify this effect, but they do not produce the color pink. The expectation of a pink color is a misinterpretation of the name’s origin, which is rooted in terrestrial biology, not celestial optics.
The Origin of the Name
The name “Pink Moon” stems from the traditions of various Native American tribes, most notably the Algonquin people. These cultures tracked time using a lunar calendar, naming each full moon after natural events that occurred during that month. These names served as a seasonal marker for activities like hunting, planting, and harvesting.
The April full moon was named to reflect the widespread blooming of a specific early spring wildflower native to the eastern United States. This plant is Phlox subulata, commonly known as Moss Pink or Wild Ground Phlox. The plant forms dense, low-growing mats that produce blankets of vibrant pink or magenta flowers across the landscape.
The full moon’s name is a celebration of the season’s first widespread flowering and the renewal of life. While the Algonquin are credited with the “Pink Moon” name, other cultures had their own names for the April full moon that also referenced spring. Examples include the Sprouting Grass Moon, the Egg Moon, and the Fish Moon, noting the return of shad swimming upstream. These diverse names underscore the moon’s traditional role as a timepiece marking seasonal changes.