The practice of naming the monthly Full Moon dates back to ancient times, serving as a traditional calendar system to track changing seasons and agricultural cycles. These names often originate from Native American, Colonial American, or European folklore, marking a distinct seasonal event. The “Coral Moon” is a modern or regional designation for the Full Moon that occurs in June, joining a long list of traditional monikers associated with the start of summer.
Defining the Coral Moon
The Coral Moon is defined by its timing, referring to the Full Moon that takes place during June. A Full Moon occurs when the Earth is positioned between the Sun and the Moon, causing the entirety of the Moon’s near side to be illuminated. This alignment makes the Moon appear as a complete, luminous disk in the night sky. The June Full Moon is a predictable astronomical event, though the exact day shifts within the month due to the Moon’s 29.5-day cycle.
The Origin of the Name
The name “Coral Moon” is likely a regional or modern variant, contrasting with the far more common June Full Moon name, the “Strawberry Moon.” This primary name comes from Algonquin, Ojibwe, Dakota, and other Native American traditions, marking the season when wild strawberries ripen. Historical lunar names consistently link the event to tangible seasonal changes, which is why other regional variants include the Rose Moon, referencing the rose bloom, and the Hot Moon, denoting the start of summer’s heat.
The use of “coral” may reference the warm, reddish-pink color associated with precious coral, aligning with the visual appearance of a low-hanging summer moon. Another possible inspiration is the phenomenon of mass coral spawning, where corals release their gametes into the water, often synchronized with the Full Moon phase in late spring or early summer.
Visual Characteristics
The June Full Moon often takes on a reddish, orange, or warm “coral” hue when low on the horizon, an effect that is purely atmospheric and unrelated to the Moon itself. This coloration results from Rayleigh scattering, the same process that causes red sunsets. When the Moon is near the horizon, its reflected light must travel through a much greater depth of Earth’s atmosphere than when it is overhead.
As the light traverses this thicker layer of air, molecules and airborne particles scatter away the shorter, bluer wavelengths. This leaves the longer, redder wavelengths to reach the observer’s eye, giving the Moon a distinctly warm appearance. Additionally, the June Full Moon can look enormous as it rises, a common psychological effect called the Moon Illusion. This illusion makes the Moon appear much larger when viewed near foreground objects on the horizon, though its actual angular size remains constant.
The Astronomical Cycle
The June Full Moon occurs close to the Summer Solstice, which directly affects its path across the sky in the Northern Hemisphere. The Full Moon always happens when the Moon is opposite the Sun. Since the Sun reaches its highest point of the year at the Summer Solstice, the June Full Moon naturally takes the lowest path across the night sky for the entire year.
This low trajectory causes the Moon to spend less time above the horizon, resulting in a shorter visible arc. Conversely, observers in the Southern Hemisphere experience the June Full Moon as the highest of the year, as it coincides with their Winter Solstice. This difference in altitude is a consequence of the Moon’s orbit, which is tilted relative to the Earth’s orbit around the Sun, causing the Moon’s path to shift throughout the year.