Begin with the birthday ranges
The twelve familiar date ranges give a convenient first approximation for a tropical Sun sign. They are not a substitute for calculating the Sun’s position at the instant of birth. Leap years and the timing of solar ingress can shift a boundary from the date shown in a simple list.
What a cusp actually means here
A boundary is a particular longitude, not a period during which the Sun occupies two signs. Within a chosen zodiac system, a calculated Sun position falls in one sign. Identifying with neighboring descriptions is possible, but it does not establish that you have two Sun signs.
When more information helps
If your birthday falls near a boundary, use the birth year, time and appropriate time offset to calculate the position. If the time is unknown, check the range of possible positions across the day and be honest about uncertainty. Tropical and sidereal systems use different reference points, so label the system as well.
Original editorial guide · Reviewed October 2026 · Our approach to astrology
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