Direct Answer: Waning Gibbous Precedes Full Moon
The lunar phase that comes directly before the full moon phase is the waning gibbous phase. In the standard 8-phase lunation cycle used by NASA and the US Naval Observatory, the sequence moves from new moon to waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent. The waning gibbous phase begins immediately after the full moon and is the phase that precedes the next full moon in the cycle NASA.
During waning gibbous, the Moon appears more than half illuminated but decreasing in visible lit area each night. This phase occurs when the Moon is past opposition and the Earth-Moon-Sun angle shifts so that the illuminated fraction visible from Earth shrinks. The phase is sometimes confused with waxing gibbous, but waxing gibbous comes before full moon, while waning gibbous comes after full moon and before the third quarter phase timeanddate.com.
Waxing Gibbous vs Waning Gibbous and the Full Moon Sequence
Waxing Gibbous Is the Phase Immediately Before Full Moon
The phase that comes directly before the full moon phase is the waxing gibbous phase. In the 8-phase lunation model, waxing gibbous follows the first quarter moon and leads into the full moon. During this phase, more than half of the Moon's Earth-facing side is illuminated, and the lit portion grows each night until the Moon reaches 100% illumination at the full moon Space.com.
Key Timing and Illumination Facts
Waxing gibbous typically lasts about 7.4 days, with illumination increasing from roughly 50% to 99%. The exact duration can vary slightly due to the Moon's elliptical orbit and its inclination relative to the ecliptic plane. The full moon occurs when the geocentric apparent ecliptic longitudes of the Sun and Moon differ by exactly 180 degrees, making the Moon fully illuminated as seen from Earth US Naval Observatory.
Lunation Cycle Order and How to Track Moon Phases
Standard 8-Phase Lunation Sequence
The widely used lunation sequence is new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent. In this sequence, waxing gibbous is the phase that comes directly before the full moon phase, while waning gibbous is the phase that comes directly after it. This standardized model is used by timekeeping authorities, astronomy apps, and educational resources worldwide.
How to Identify the Phase Directly Before Full Moon
To identify the phase directly before the full moon, look for a Moon that is more than half lit and growing brighter each night. The terminator line, the edge between the lit and dark portions, is shrinking as illumination increases. When the Moon reaches 100% illumination, it transitions from waxing gibbous to full moon. Tracking tools from NASA and timeanddate.com provide daily phase data, illumination percentages, and exact times for each phase change NASA.