A new moon is when the Sun and Moon line up in the same sign and degree, and a full moon is when they sit directly opposite each other. In astrology, the new moon is linked with starting things and the full moon with things coming to a head. The whole cycle takes about 29.5 days, so each one comes around roughly once a month. Many people use them as monthly check-ins: set an intention at the new moon, then review it at the full moon.
The Moon does not make its own light. We see the half of it that the Sun is lighting up, and how much of that half faces us changes as the Moon orbits Earth.
At the new moon, the Moon sits between Earth and the Sun. The lit side faces away from us, so the Moon is dark and rises and sets with the Sun. Astrologers call this a conjunction: the two bodies share the same degree of the zodiac.
At the full moon, Earth sits between them. The whole lit side faces us, and the Moon rises around sunset. This is an opposition: the Sun and Moon are 180 degrees apart, in opposite signs.
Halfway between them come the quarter moons, when the Sun and Moon are 90 degrees apart and half the Moon's face is lit. From one new moon to the next takes about 29.5 days. That is why there are usually twelve new moons in a year, and occasionally thirteen.
Between the new and full moon, the Moon passes through a set of phases. Each has a traditional meaning in astrology.
A new moon always happens in the sign the Sun is in at the time. So the new moon each spring falls in Aries, the next one in Taurus, and so on through the year.
A full moon falls in the sign opposite the Sun. When the Sun is in Taurus, the full moon is in Scorpio. That makes each full moon a tension between two signs, which astrologers read as a moment to balance their themes.
For example, Taurus is about comfort, security and what you own. Scorpio is about depth, trust and what you share with others. A full moon across these two signs is often read as a good time to look at the balance between keeping things safe and letting someone in. The Taurus and Scorpio pairing shows the same tension in relationships.
The sign sets the general theme for everyone. The house makes it personal. Each new or full moon lands in one of your twelve houses, and that house shows the area of life it lights up for you.
Say the Sun is at 20 degrees Taurus, so the full moon falls at 20 degrees Scorpio. If 20 Scorpio lands in your sixth house, the house of work routines and health habits, the traditional reading is that daily routines come into focus. Something you have been working on may reach a result, or you may see clearly what needs changing.
It is read as stronger when the degree falls close to a planet in your chart. A new moon within a few degrees of your natal Venus, for instance, might be read as a good moment to start something around love, beauty or money.
You do not need to believe the Moon causes anything to find the cycle useful. It is a steady monthly rhythm, and rhythms help people reflect.
Keep it gentle. The cycle is a prompt for reflection, not a schedule you have to obey.
Every eclipse is also a new or full moon. A solar eclipse is a new moon that lines up closely with the lunar nodes, and a lunar eclipse is a full moon that does the same.
This only happens during eclipse seasons, roughly every six months. Astrologers read eclipses as stronger, longer-lasting versions of the ordinary monthly cycle. The eclipses guide covers them in detail.
Any calendar will tell you the date and sign of the next new or full moon. To go further, you need to know which house that degree lands in for you, which depends on your birth time.
Start by looking at your own birth chart and noting the sign on each house cusp. Then, when a new moon comes up, you can see at a glance which part of your life it touches.
About 29.5 days from one new moon to the next. The full moon falls roughly halfway through, about two weeks after the new moon.
Always the sign opposite the Sun. If the Sun is in Leo, the full moon is in Aquarius. The new moon is in the same sign as the Sun.
In astrological tradition, yes. The new moon is linked with beginnings and setting intentions, while the full moon is linked with results and completion.
Astrology traditionally links full moons with heightened emotion. People experience this differently, and noticing your own patterns over a few months is the best way to see if it applies to you.