Thanks to our lunar cycle, the moon is always changing how it appears to us. Tonight’s moon is a little shy, and we can explain why.
The lunar cycle is a series of eight phases of the moon’s visibility, based on how much light the sun shines on it. The whole cycle takes about 29.5 days, according to NASA, and these different phases happen as the Sun lights up different parts of the moon whilst it orbits Earth.
Here’s what the moon is doing today, June 21, 2025.
What is today’s moon phase?
As of Saturday, June 21, the moon phase is Waning Crescent. In this phase, the moon is only slightly lit and not very visible to us on Earth. According to NASA, this moon is 21% visible.
As the moon becomes less and less visible, this marks the end and almost the beginning of a new lunar cycle. Today we’re on day 25. This level of visibility doesn’t reveal much to us, but we can see the Aristarchus Plateau. A crater with a diameter of 25 miles, created when a lava formation collapsed. This can be seen with the naked eye, so you don’t need to arrange any fancy equipment.
However, if you do have access to binoculars, you’ll also be able to spot the Grimaldi Basin and the Gassendi Crater.
For the Northern Hemisphere, this will appear in the top left. If you’re in the Southern Hemisphere, the bottom right.
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When is the next full moon?
June’s full moon was on June 11. The next full moon will be on July 10.
What are moon phases?
As we hit day 25, what are the other phases of the 29.5-day lunar cycle, and why do they happen? NASA tells us that these phases are caused by the angles between the sun, moon, and Earth. Moon phases are how the moon looks from Earth as it goes around us. We always see the same side of the moon, but how much of it is lit up by the Sun changes depending on where it is in its orbit. So, sometimes it looks full, sometimes half, and sometimes not there at all. There are eight main moon phases, and they follow a repeating cycle
New Moon – The moon is between Earth and the sun, so the side we see is dark (in other words, it’s invisible to the eye).
Waxing Crescent – A small sliver of light appears on the right side (Northern Hemisphere).
First Quarter – Half of the moon is lit on the right side. It looks like a half-moon.
Waxing Gibbous – More than half is lit up, but it’s not quite full yet.
Full Moon – The whole face of the moon is illuminated and fully visible.
Waning Gibbous – The moon starts losing light on the right side.
Last Quarter (or Third Quarter) – Another half-moon, but now the left side is lit.
Waning Crescent – A thin sliver of light remains on the left side before going dark again.
