Lunar Calendar Explained: Converting Dates, Zodiac & Constellations

Your grandparents only remember you were born on the 23rd of the twelfth lunar month, but every form asks for a Gregorian date. And is the zodiac decided by New Year or by Lichun? Let's untangle it once and for all.

Two Different Calendar Systems

• Gregorian (solar): one year = one orbit of the Earth around the Sun, ~365 days. This is the calendar on IDs and passports.
• Lunar (lunisolar): months follow moon phases (~29.5 days), with a leap month added every 2-3 years to stay aligned with the solar year. That is why lunar birthdays shift every Gregorian year.
• Leap month: some years have two of the same month, e.g. a 'leap 4th month'. People born in a leap month usually celebrate on the regular month, or both.

Which Day Decides Your Zodiac Animal?

The folk rule: Chinese New Year (lunar January 1st) starts a new zodiac year. The stricter astronomical rule uses Lichun (Start of Spring, around Feb 4). For everyday purposes use New Year; traditional fortune-telling often prefers Lichun. When unsure, look the year up with a tool instead of guessing.

Constellations Always Use the Gregorian Date

Western astrology is inherently Gregorian. The most common mistake is matching a lunar birthday against sign charts — lunar July 7th usually falls in August, which is Leo territory, not Cancer. Convert the lunar date to Gregorian first, then check the sign.

FAQ

Which birthday should I celebrate?

Follow your family tradition — lunar for most households. A practical tip: set two yearly reminders in your phone calendar, one for each date.

Did NASA change the zodiac signs?

No. The viral '13th sign Ophiuchus' story confuses astronomical constellation boundaries with the fixed astrological date table. Astrologers never changed their charts.