What usually stays the same
Your Sun sign, unless you were born on the day it changes, and the positions of the slower planets. For many people an hour either way changes nothing important. For some it changes a lot, and the date alone can't tell you which.
What can change
- Your rising sign: it changes about every two hours on average, and a birth chart needs the time to place it.
- Your Moon: it changes sign about every two and a half days, so being born on one of those days can matter.
- Your Human Design: the numbers in your profile can change within a day, and a small shift can change which of your centers are colored in, and sometimes your type.
Where to find it
- A birth certificate, where your country records the time. Many do, though not all.
- The hospital or registry where you were born, which may keep records you can ask for.
- Parents and relatives, baby books and old letters.
If you don't know it
You can still have a chart. It helps to treat the fast-moving parts as less certain, and to look for what stays the same across the hours you might have been born. When Ally draws a chart from an uncertain time, it marks the parts that affects.
The detail, if you want it
The houses of a birth chart move with the rising sign. In Human Design, the Moon crosses a gate in about ten hours and the Sun crosses a line in a little under a day, on both the black and the red side. A change in a single gate can complete a channel or leave it open, and if that channel is what decides your type, the type changes too.
Written with AI and reviewed by a person at Stellar Ally AB. Published November 3, 2026.
Human Design and its terminology originate with their respective authors and rights holders. Stellar Ally AB is independent and unaffiliated, and claims no trademark rights in the Human Design System. Ally uses these systems as one lens for self-reflection, nothing more. Nothing in Ally is medical, psychological, legal, or financial advice.