What Exactly is My Sun Sign?
Your Sun Sign is the sign of the Zodiac that the Sun occupied the moment you were born. For example, the Sun was in Gemini on June 9th so if you were born on June 9th then your Sun Sign is Gemini. When someone at a party asks "What's your sign?" this is what he is asking about. He's also trapped in a 70's time warp and watches old videos of Charlies Angels but that's a different subject.
Most of us know what our Sun Sign is. This is the heading we look under when we look at our "horoscope" in the paper. A few people (about one in thirty) are born on The Cusp or edge of two signs. If you were born on the Cusp then you have to check exactly where the Sun was at the moment of your birth to truly determine which of the two signs will dominate your personality. The Sun moves from one sign to the next with exact precision but the change from one sign to the next does not occur at the same time every year, In fact, it may not occur on the same date! So if you were born on March 20, 1979 you would be an Aries BUT if you were born on March 20, 1978 you would be a Pisces!
There are three ways to find out which you are. One way is to analyze your personality and see which of the two signs you most resemble. The other is to consult a book called an Ephemeris which is a big thick book of astrological data that gives the position of each of the planets for all the times in each year (now you know why it's big and thick) Oh, and the third way to find out is to have an Astrologer cast a BIRTH CHART for you.