The lunar cycle is the predictable shift in the Moon’s appearance resulting from the changing geometry between the Sun, Earth, and Moon. This cycle takes approximately 29.5 days to complete. The term “waxing” refers specifically to the first half of this cycle, spanning the roughly two weeks between the New Moon and the Full Moon. During this time, the illuminated portion we observe is increasing due to the Moon’s continuous orbital motion.
Defining the Waxing Phase
The astronomical meaning of “waxing” derives from an Old English word meaning “to grow” or “to increase.” The Moon itself does not generate light but reflects the Sun’s illumination, meaning half of its spherical surface is always lit. From our perspective on Earth, we only see a portion of this sunlit half, and the size of that visible portion changes as the Moon travels in its orbit.
The waxing phase begins immediately after the New Moon, when the Moon is positioned roughly between the Earth and the Sun, making the sunlit side face mostly away from us. As the Moon moves counter-clockwise in its orbit, its angle relative to the Earth and the Sun gradually widens. This widening angle allows the terminator line, the boundary between the sunlit and shadowed parts of the Moon, to shift across the face visible to us. This causes the illuminated fraction to grow larger each night until the Moon reaches the Full Moon phase.
The Sequential Stages of Waxing
The journey from the invisible New Moon to the fully illuminated Full Moon is divided into three stages. The first visible stage is the Waxing Crescent, which appears as a thin, curved sliver of light immediately following the New Moon. During this stage, less than half of the Moon’s face is illuminated, and the percentage of light increases from nearly zero to just under fifty percent.
Following the crescent is the First Quarter Moon, which occurs when the Moon has completed one-quarter of its orbit around the Earth. At this point, the Moon appears exactly half-illuminated. The light then continues to expand into the Waxing Gibbous stage, characterized by the Moon appearing more than half-lit but not yet completely full. The term “gibbous” refers to this convex, bulging shape, and this stage lasts until the Full Moon phase.
How to Tell Waxing from Waning
Distinguishing the waxing phases from the waning phases is a common challenge for observers, but a reliable method exists for those in the Northern Hemisphere. If the Moon is illuminated in the shape of a capital letter “D,” it is a waxing Moon, or “Developing.” Conversely, if the illuminated portion resembles the letter “C,” it is a waning Moon, or “Concluding.”
Another practical method is to note the side of the Moon that is illuminated. In the Northern Hemisphere, the light always appears on the right side during the entire waxing period. As the Moon progresses from New to Full, the right side fills with light until the whole disk is bright. After the Full Moon, the light recedes from the right, meaning the illuminated portion is on the left side during the waning period.
Cultural Interpretations of a Waxing Moon
Beyond its astronomical definition, the Waxing Moon has historically carried meaning in various human cultures and traditions. Because the visible light of the Moon is progressively increasing, this period is associated with growth, expansion, and the building of energy. The visible journey from darkness to light often symbolized creation and the manifestation of intentions.
Many traditions viewed the Waxing Moon as a time for new endeavors, such as setting goals, beginning projects, or undertaking ceremonies. In agricultural practices, the increasing light was seen as beneficial for planting crops that grow above ground, contrasting with the waning period which favored root crops. The growing luminosity represented a period of increasing positivity, prosperity, and the gathering of power in spiritual and folkloric belief.