Astroyana research · sign distribution

How do assumed birth patterns change sign frequencies?

Uniform sampling gives a mathematical base rate. This study compares it with assumed monthly and hourly weights, using 100,000 synthetic charts per regime. It shows sensitivity to sampling assumptions; it does not estimate a real population or validate life outcomes.

This is a scenario analysis under assumed weights, not an estimate of India’s birth population. The monthly weights lack a traceable publication or table; the hourly shape is adapted from a US report and the 40% scheduled share is assumed. The 2.81× result depends on those inputs. A near-uniform Moon distribution is a useful diagnostic, not proof that the model is unbiased.

Your Sun sign is set by the season you were born in

The uniform sample has Sun-sign total variation distance 1.16 percentage points from an even distribution. The assumed monthly vector weights August–September more and April less. In the weighted scenario Leo reaches 12.8% and Pisces 4.55%; total variation distance is 14.99 points. These values depend on the chosen weights.

Rising signs differ modestly between these two regimes

The ascendant is the one placement people assume hospital scheduling must distort, since it turns on the clock. The truth is more interesting. Even under uniform time, the rising sign is already uneven — Scorpio rises in 9.38% of charts but Pisces in only 6.38% (1.47×). That's pure astronomy: at Indian latitudes some signs take much longer to climb the eastern horizon than others, so more births fall under the slow risers.

Changing both weights gives a largest rising-sign difference of 0.82 percentage points. Total variation distance moves from 6.02 to 6.23 points. This comparison combines the assumed seasons, hours and finite-sample variation; it does not separately measure a hospital-scheduling effect.

Moon distributions are nearly even in this scenario

Under these weights, Moon-sign total variation distance from evenness is 0.62 percentage points. The largest-to-smallest nakshatra share differs by 0.28 points. These are diagnostics of this scenario, not proof of unbiased sampling or uniform Moon distributions in every population.

What this means

The twelve signs are not evenly distributed in this assumed sampling scenario. Sun-sign frequency reflects the birth season, rising-sign frequency reflects how long each sign takes to ascend, and Moon signs remain close to evenly distributed. A sign can therefore be statistically uncommon because of the calendar or rising geometry. The chart calculation shows which explanation applies.

Methodology

Synthetic scenario study — no real user data. Two independently drawn regimes share a fixed seed and one engine: uniform date/hour sampling and the legacy-named 'realistic' regime under assumed monthly and hourly weights. The monthly vector has no traceable primary publication/table; the hourly vector is hand-shaped from a US report and the scheduled share is assumed to be 40%. At zero scheduled share the hour marginal becomes uniform, but monthly seasonality remains. Both priors change together, so this comparison does not isolate hospital scheduling. Near-uniform Moon distributions are diagnostics, not proof of unbiasedness. Figures are conditional base rates under these inputs, not an estimate of India's population. N is the sample size per regime.

With N=100,000 the 95% Monte-Carlo half-width of a published percentage is ±0.31 points near 50% and ±0.14 points near 5%. That is the uncertainty of the base rate itself; because the seed is fixed, re-running the script on the same engine reproduces every figure exactly.

Sample size

1,00,000 charts

Birth date range

1950-01-01 to 2009-12-31

Timezone

IST (UTC+5:30)

Birth hour

uniform baseline vs. assumed business-hours scenario

Locations

population-weighted across 25 major Indian cities

Ayanamsa

lahiri

Nodes

mean

House system

whole_sign

Engine version

0.14.0

Engine commit

8cff3aad679b

Swiss Ephemeris

2.10.03 (pyswisseph 2.10.3.2)

Precision (95%)

±0.31 pp

Generated on

2026-10-10

Dataset revision

2

Seed

20260603

Uniform draws dates and hours evenly. The legacy-named realistic regime uses assumed monthly weights and an hourly shape adapted from a US report, with an assumed 40% scheduled share. At zero share, hours become uniform but monthly seasonality remains. The regimes use different birth draws; their differences include both changed priors and finite-sample variation.

FAQ

Related: does a one-hour birth-time error rewrite your chart? and does astrology agree with itself?

Free to cite with attribution to Astroyana. Figures are the mathematical base rate per birth moment from a synthetic sample, computed with our Swiss-Ephemeris (Lahiri) engine — not a survey of real people, and not a claim about anyone’s life.