The astronomical boundary
It is the exact instant when the Sun reaches 0°, 30°, 60°… Your time and the time zone of your city decide which side you were on.
Were you born on a zodiac cusp?
The threshold between two signs
You are not “half one sign and half another.” The Sun occupied one exact point when you were born. Find it and see whether it was within 3° of a zodiac boundary.
real position of the Sun
What it really means to be born near a cusp
Popular tables place the change on the same date every year, but the Sun does not follow a fixed calendar: it may enter a sign at a different hour each year.
The symbolic zone
We use a restrained 3° band before or after the boundary—roughly three days—to describe proximity, not to change your sign.
If you do not know the time
We check the whole day. If the Sun changed signs, we show both possibilities instead of giving you a false answer.