September 11, 2025 Current Southern Hemisphere/Tomorrow’s Northern Hemisphere Moon Phase

You can find more moon phase details on both of the websites used in this post by clicking on the hyperlink.

Source: nineplanets.org

The Moon phase for September 11th, 2025 is a Waning Gibbous phase. This is the first phase after the Full Moon where the illumination of the moon decreases each day until it reaches 50% (the Last Quarter phase).

The waning (shrinking) gibbous Moon will rise after sunset in the east, transit the meridian after midnight, before setting after sunrise in the west.

During this phase, the illumination of the moon will go down from 99.% to 50.1%. Technically, the phase starts as soon as the Full Moon has passed, but it can be difficult to calculate and differentiate the first stage of a Waning Gibbous Moon from a Full Moon when 98-99% of the Moon’s surface is illuminated.

Fun fact:

Phase Details

Phase: Waning Gibbous

Moon age: 18.65 days

Moon illumination: 86.24%

Moon tilt: -70.853°

Moon angle: 0.55

Moon distance: 364,910.99 km

Moon sign: Taurus

Source: MoonGiant.com

You can use this link to go forward or backward in time for Moon phase information. If you are curious, you can even find out what phase the Moon was in when you or anyone else was born.

Today’s Waning Gibbous Phase

The Waning Gibbous on September 11 has an illumination of 80%. This is the percentage of the Moon illuminated by the Sun. The illumination is constantly changing and can vary up to 10% a day. On September 11 the Moon is 19.12 days old. This refers to how many days it has been since the last New Moon. It takes 29.53 days for the Moon to orbit the Earth and go through the lunar cycle of all 8 Moon phases.

Phase Details