Today the Moon will be in a Waning Crescent phase. In this phase the Moon’s illumination is growing smaller each day until the New Moon. During this part of the Moon cycle, the Moon is getting closer to the Sun as viewed from Earth and the night side of the Moon is facing the Earth with only a small edge of the Moon being illuminated. This phase is best viewed an hour or 2 before the sunrise and can be quite beautiful if you’re willing to get up early. It can also be a great time to see the features of the Moon’s surface. Along the edge where the illuminated portion meets the dark side, the craters and mountains cast long shadows making them easier to observe with a telescope or binoculars.
Visit the May 2021 Moon Phases Calendar to see all the daily moon phase for this month.
Today’s Waning Crescent Phase
The Waning Crescent on May 4 has an illumination of 43%. 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 May 4 the Moon is 22.81 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.
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, you know was on the date the person was born.