Moon Phases Explained
The Moon goes through 8 distinct phases during its 29.5-day cycle. Each phase changes when the Moon rises and sets, how bright it appears, and even affects Earth's tides.
The Lunar Cycle
Moon phases are caused by the changing angle between the Sun, Earth, and Moon as the Moon orbits our planet. We see different amounts of the Moon's sunlit surface depending on the Moon's position in its orbit.
The complete cycle from one New Moon to the next takes 29.53 days — known as a synodic month or lunation. This is slightly longer than the Moon's orbital period (27.3 days) because Earth is also moving around the Sun, so the Moon needs a little extra time to return to the same Sun-Earth-Moon alignment.
The 8 Phases of the Moon
New Moon
Phase 1 of 8The Moon is between Earth and the Sun, with its illuminated side facing away from us. The Moon is invisible or nearly invisible in the sky.
Waxing Crescent
Phase 2 of 8A sliver of the Moon becomes visible on the right side (in the Northern Hemisphere). The illuminated portion grows larger each day.
First Quarter
Phase 3 of 8Exactly half of the Moon's visible face is illuminated. This occurs roughly 7 days after the New Moon. The right half is lit in the Northern Hemisphere.
Waxing Gibbous
Phase 4 of 8More than half the Moon is illuminated, growing toward full. "Gibbous" comes from Latin meaning "humpbacked."
Full Moon
Phase 5 of 8The entire face of the Moon is illuminated by the Sun. The Moon is on the opposite side of Earth from the Sun. This is when the Moon is at its brightest.
Waning Gibbous
Phase 6 of 8The Moon's illumination begins to decrease after the Full Moon. The left side begins to darken (in the Northern Hemisphere).
Last Quarter
Phase 7 of 8Exactly half the Moon is illuminated — the left half in the Northern Hemisphere. This is the mirror image of the First Quarter.
Waning Crescent
Phase 8 of 8A thin sliver of light remains on the left side of the Moon (Northern Hemisphere). The illumination shrinks each day toward the next New Moon.
How Moon Phases Affect Moonrise and Moonset
The Moon's phase directly determines when it rises and sets:
- New Moon rises and sets with the Sun — it's above the horizon during the day
- First Quarter rises at noon and sets at midnight
- Full Moon rises at sunset and sets at sunrise — visible all night
- Last Quarter rises at midnight and sets at noon
Between these key phases, the rise and set times shift gradually. Each day, the Moon rises and sets approximately 50 minutes later than the day before.
Use our calculator to find precise moonset times for your location.
Supermoons and Micromoons
Because the Moon's orbit is elliptical, its distance from Earth varies. When a Full Moon coincides with the Moon's closest approach (perigee), it's called a Supermoon. A Supermoon can appear up to 14% larger and 30% brighter than a Micromoon (Full Moon at apogee).
There are typically 3-4 Supermoons per year. While the size difference is subtle to the naked eye, the brightness difference is noticeable, especially in areas with little light pollution.
What Phase Is the Moon In Right Now?
Our calculator shows today's moon phase, illumination percentage, and exact moonset time for your location.
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