Phases are angles, not appearances
The phase of the Moon is the angular distance between it and the Sun as seen from Earth. At zero degrees it is new and invisible, at ninety it is a half disc growing, at one hundred and eighty it is full, at two hundred and seventy it is the other half disc shrinking. Everything between has a name only by convention.
Because the Moon travels about thirteen degrees a day, the whole cycle takes 29.53 days on average, the synodic month. That is longer than the 27.32 days the Moon takes to go once round the sky, because in the meantime the Sun has moved on and the Moon has to catch it.
The average hides real variation. The Moon's orbit is elliptical and perturbed by the Sun, so an individual lunation can run from about 29.27 to 29.83 days. The times in the table are solved for each event rather than stepped forward from the average, so they are exact rather than approximate.
Why the sign matters more than the phase name
Every new moon does the same thing astronomically. What differs between them is where in the zodiac they land, and therefore which part of a chart they fall in. A new moon at fifteen degrees of Taurus and a new moon at fifteen degrees of Scorpio are the same event on opposite sides of the sky.
This is why the degree column is here. If you want to know whether a lunation is doing anything to your chart, the question is whether that degree sits close to one of your own placements, not whether the sign matches your sun sign. Comparing degrees is a minute's work and it removes almost all of the guessing.
Blue moons, supermoons and the other popular names
A blue moon in modern usage is the second full moon in a calendar month, which happens roughly every two and a half years because 29.53 days fits inside most months with room to spare. The older definition, from an almanac tradition, is the third full moon in a season containing four. Neither has anything to do with colour.
A supermoon is a full moon near perigee, the closest point of the Moon's orbit. It is genuinely larger, by around fourteen per cent in diameter against the smallest full moons, which is a real difference that is nearly impossible to notice without a photograph for comparison.
A black moon usually means a second new moon in a month, by symmetry with the blue moon, though the term is used loosely enough that it is worth asking which sense someone means.
The equinoxes and solstices in the same year
The table at the foot of the page gives the four seasonal turning points. The March equinox is the moment the Sun crosses the celestial equator going north, which is also the moment it enters Aries and therefore the origin of the entire tropical zodiac. The June solstice is its furthest north, the September equinox its southward crossing, the December solstice its furthest south.
These are the four cardinal ingresses, and in astrological practice a chart cast for one of them is read as describing the season it opens. They are included here because they are computed by exactly the same machinery and because a year's calendar is incomplete without them.
Questions people ask about this
Why is the full moon time different from the one my app shows?
Almost always a time zone. Every time here is UTC, and a full moon at 02:00 UTC is the previous evening in the Americas. The instant is identical, only the clock reading differs.
What sign is the full moon in?
Whichever sign the Moon occupies at the moment of opposition, which is always the sign opposite the Sun. During Leo season the full moon is in Aquarius, and so on round the wheel.
How many full moons are there in a year?
Twelve in most years and thirteen in some, because twelve synodic months come to about 354 days and the calendar year is eleven days longer. The surplus accumulates until an extra one fits.
Is a new moon a good time to start something?
That is a convention rather than a finding, and this page does not make claims about it. What the page gives you is when the new moons are, in what sign and at what degree, which is the part you can verify.
Why are the first and last quarter moons not listed?
The table shows the two syzygies, the alignments, because those are the ones that carry astrological weight and the ones that produce eclipses. The quarters are computed by the same method and could be added, but they are rarely what anyone came looking for.
Do the phases look different in the southern hemisphere?
The timing is identical and the illuminated fraction is identical. What flips is the orientation: a waxing crescent that opens to the right in London opens to the left in Melbourne, because you are looking at it upside down relative to each other.