If the sun in your birth chart represents what you need for your personal growth, the moon shows us what you need on an even deeper level. Moon is where your emotions stem from, and your deepest desires, and your deepest sense of security, and your most deeply unconscious beliefs, feelings, and reactions. It shows how you’re inclined to process emotion, what you need to feel secure, what makes you feel the most at home. Moon sign and house reflect what you’re inclined to want in your home. They also reflect your family of origin, ancestors in general, your early experience of family life, how you were parented (especially by the mother), and if you yourself are a parent, your likely approach to the emotional aspects of parenting. 

To be well functioning is to be making positive responses to both your moon and your sun. Sometimes the moon and sun require similar things. Sometimes they represent very different, but equally important, needs. Either way, we all need a balance of moon and sun in our lives.

Steven Forrest assigns archetypes to each sign and a quick shorthand for sketching out sun, moon, and rising: you are your sun sign archetype, with the soul of your moon sign archetype, wearing the mask of your rising sign archetype. Or, we could say your sun is your brain and moon is your heart (however, this is just in a poetic sense. Astrological correlations with the body give the sun rulership over the heart and circulatory system and the moon rulership over the belly, stomach, and all hollow organs.)

Determining your moon sign takes slightly more work than determining your sun sign. Just knowing when your birthday is, day and month, does not reveal your moon sign, because which sign the moon is in on a given date varies from year to year. For example, one April 1st might see a new Aries moon, while another sees a full Libra moon, and yet another sees a Gemini moon. 

Knowing the year you were born as well as day and month does reveal moon sign for over half of the population, and for the rest, narrows the possible moon signs down to two. The moon changes signs every 2 ½ - 3 days. Consequently, slightly more than a third of us were born on a day when the moon changed signs. If you are one of those people, you need to know your birth time to determine whether you were born before or after the lunar sign change.

Where your moon is in relation to your sun tells you which phase of the moon you were born in. If your moon and sun signs are the same (double Libra, double Taurus, etc.), you were born during a new moon. If they’re opposite signs (Leo and Aquarius, Virgo and Pisces, etc.), you were born during a full moon. Anywhere in between reflects the in between new and full phase you were born in.

If your moon sign comes later in the zodiac than your sun sign but earlier than the sign opposite your sun, you were born during a waxing moon. If it’s earlier than your sun but later than the sun’s opposite sign, you were born during a waning moon. While the details are beyond the scope of this post, the phase of the moon in your natal chart adds an overall tone to the theme of your life. (More on that sometime later).

The moon is the fastest moving of the astrological planets, taking approximately 27 days to go through the whole zodiac. Some people find that they feel especially emotional, or in some cases especially energized, whenever the moon moves into their natal moon sign. Others do not notice this in particular.

It’s quite common for people to not feel like their sun signs, or at least not much like the usual descriptions of the personality their sun sign is supposed to have. Often, who we feel we are has a closer resonance with our natal moon than with our sun. For approximately 11 out of every 12 people, the moon and sun are in different signs. Even for those with the moon and sun in the same sign, there’s also the rising sign to consider, which may be quite different from the moon/sun placement.

Up next: Rising Sign: Where It All Comes Together