Pick a date and time to see what the moon looks like, how much of it is lit, and when the next full and new moons are. Times are in your device’s time zone. The view is flipped for the southern hemisphere, where the moon appears upside down compared with the north.
| Phase | Date & time |
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The moon doesn’t make its own light: we see the half facing the sun. As it orbits the Earth every 29.53 days (a synodic month), the angle between the sun, Earth and moon changes, and we see more or less of the lit half. At new moon it sits roughly between us and the sun and the lit side faces away; at full moon it is on the far side of the Earth from the sun and we see the whole lit face.
Waxing means the lit part is growing (new → full), waning means it’s shrinking (full → new). Crescent is less than half lit, gibbous more than half. The quarters are named for being a quarter of the way through the cycle, even though half the disc looks lit.
The exact times of new, quarter and full moons come from Meeus’s Astronomical Algorithms (chapter 49), with the full set of periodic corrections. The percentage lit uses the sun–moon phase angle (chapter 48). The “moon age” is the time since the last new moon.
In the northern hemisphere a waxing moon is lit on the right; in the southern hemisphere, on the left. Near the equator the crescent lies more on its back, like a smile.
It’s shown above for the date you choose, in your time zone. Full moons come about every 29.5 days, so most months have one, and roughly every two and a half to three years a month has two; the second is popularly called a blue moon.
The number of days since the last new moon. It runs from 0 to about 29.5: around 7.4 days is first quarter, around 14.8 is full moon, and around 22 is last quarter.
People in the south view the moon upside down compared with the north. So a waxing crescent, lit on the right in London or New York, is lit on the left in Auckland or Sydney.
Yes, the phase is the same everywhere at the same instant. The local date and time of a full moon differ by time zone, so it can fall on different calendar dates in different countries.
Waxing means the lit part is growing each night, heading towards full moon. Waning means it is shrinking, heading back to new moon. A waxing moon is visible in the evening; a waning moon rises late and is seen in the early morning.
