Moon Phase Calendar

Reading the Moon

The Moon makes no light of its own; we only ever see the half the Sun is lighting. As the Moon circles Earth once every 29.5 days (the synodic month), the angle between the Sun, Earth and Moon changes, so a different slice of that lit half faces us. That slow change is the cycle of phases, and the calendar above draws each day at the exact shape the Moon shows on that date. The full geometry, with a synced orbit-and-globe view, is on the Moon Phases lesson.

The four principal phases

Four moments anchor the cycle. At the new moon the Moon sits between us and the Sun and its lit side faces away, so it is invisible. About a week later the first quarter shows a half disk lit on the right. At the full moon the Moon is opposite the Sun and fully lit. Another week on, the last quarter is a half disk lit on the left. Between them the Moon is a crescent or gibbous, waxing (growing) on the way to full and waning (shrinking) on the way back to new.

Full moon names and the blue moon

Each month's full moon carries an old almanac name drawn from the seasons: the Wolf Moon of deep winter, the Strawberry Moon of June, the Harvest Moon near the autumn equinox. Because 29.5 days is a touch shorter than most calendar months, now and then a single month holds two full moons; the second is the famous blue moon, which is not really blue. Eclipses are the special case where a new or full moon lands on a lunar node, which you can chase on the Eclipse & Saros Explorer.

See more of tonight's sky

For where the planets are and what is visible right now, open Today in the Sky, and to find your local sunrise, sunset and twilight times, use the day-length calculator.

Frequently asked questions

What moon phase is it tonight?

The card at the top shows tonight's phase, drawn at the Moon's true illuminated shape, with the percent lit and whether it is waxing (growing) or waning (shrinking), plus the dates of the next full and new moons.

What time does the Moon rise and set today?

Pick a location (or tap Use my location) and the Moon tonight panel shows today's moonrise, moonset and the time and height of the Moon's highest point, in your device's time zone. Because the Moon rises about 50 minutes later each day, some days have only a moonrise or only a moonset within the calendar day.

What are the traditional full moon names?

Each month's full moon has an old almanac name: the Wolf Moon in January, Snow in February, Worm in March, Pink in April, Flower in May, Strawberry in June, Buck in July, Sturgeon in August, Harvest or Corn in September, Hunter's in October, Beaver in November and the Cold Moon in December.

What is a blue moon?

A blue moon is the second full moon in a single calendar month. Because the Moon's cycle is about 29.5 days, slightly shorter than most months, a month can occasionally hold two full moons; the second is called a blue moon. It is not actually blue.

What is a supermoon?

A supermoon is a full moon that falls near perigee, the Moon's closest point to Earth, so it looks a little larger and brighter than usual. There is no official cutoff, but a full moon closer than about 360,000 km is the common rule of thumb; such a moon looks roughly 7 percent wider and 15 percent brighter than an average full moon.

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