Moon Phase: September 17, 2021

On this day the Moon was in a Waxing Gibbous phase. Visible through most of the night sky setting a few hours before sunrise. This phase is when the moon is more than 50% illuminated but not yet a Full Moon. The phase lasts about 7 days with the moon becoming more illuminated each day until the Full Moon. This September Full Moon will be the forth and final supermoon of 2023.

During a Waxing Gibbous the moon rises in the east in mid-afternoon and is high in the eastern sky at sunset. The word Gibbous first appeared in the 14th century and has its roots in the Latin word "gibbosus" meaning humpbacked.

Visit the September 2021 Moon Phases Calendar to see all the daily moon phase for this month.

Waxing Gibbous Phase

The Waxing Gibbous on September 17 has an illumination of 87%. 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 17 the Moon is 11.24 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 for - September 17