In the days after full moon, do you sometimes look for the moon and not find it? At that time, the moon is in a waning gibbous phase: less than full but more than half-lighted. A full moon rises at sunset, but a waning gibbous moon rises later at night and appears in the morning sky.
A waning gibbous moon can surprise you if you happen to be out late in the evening. It rises eerily some hours after sunset, glowing red like a full moon when it’s near the horizon.
Sometimes it looks like a misshapen clone of a full moon.
A waning gibbous moon also initiates a rash of questions about seeing the moon during the day.
If it rises late at night, you know the waning gibbous moon must set after sunrise.
In fact, in the few days after full moon, you’ll often see the waning gibbous moon in the west in early morning, floating against the pale blue sky.
As the moon orbits Earth, it changes phase in an orderly way. Follow the link below to understand the phases of the moon.
Bottom line: A waning gibbous moon is up from late night until early morning. It’s between full moon and last quarter moon. The last full moon was September 24-25. The next last quarter moon will be October 2.
Check out EarthSky’s guide to the bright planets.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.