Waning Gibbous at birth
Waning Gibbous illustration
After full moon, the bright disk shrinks from the west. More than half remains lit for several nights.
Waning phases close the bright half of the month in many informal moon calendars.
Place in the cycle
The Moon takes a bit over twenty-nine and a half days to return to the same phase. The Waning Gibbous is the sixth of the eight labels this site uses between one new moon and the next.
How this site estimates your phase
The birthday calculator has your date, not your birth minute. We evaluate a simple average lunar cycle at local noon and map that progress into eight named windows. That is good enough for curiosity and teaching; orbital ephemerides used by observatories are tighter when you need precision.
Read more in methodology or return to the moon phases hub.
Common questions
What does a Waning Gibbous look like?
From Earth you see illumination that is more than half and shrinking. Exact appearance still depends on your latitude, the Moon's path, and weather.
How does the calculator decide I had a Waning Gibbous?
It estimates phase at local noon on your birth date with a mean synodic-month model, then bins the result into one of eight classic names.
Can the label be wrong without a birth time?
Yes, near phase boundaries. Without clock time and location, neighboring names can be equally plausible.