The position first
Noon in each year from 1930 to 2035 put the Sun on this date between roughly four and nine tenths and six and a third degrees of Cancer. Six degrees is the working figure, and the spread across the whole span stays under a degree and a half.
Six degrees falls inside the first face of Cancer, the band running from zero to ten. Every source agrees on that much. What they divide over is which planet the band belongs to.
Noon serves only as a consistent point of comparison between years. A birth at either end of the same day differs by less than a degree, which does not disturb the face or the sign.
Two ways of dividing the same band
The Chaldean order runs the seven visible planets in speed sequence, from the slowest to the fastest, and walks that sequence around the whole zodiac face by face starting from the beginning of Aries. Counting through, the opening face of Cancer arrives at Venus.
The triplicity scheme works differently. It steps through the three signs of the same element in order, so the first face of Cancer belongs to Cancer itself and takes its ruler, the Moon. Both methods are old, both are still printed, and a page quoting one is not disagreeing with a page quoting the other.
The Chaldean order is also the source of the planetary days of the week, which is a useful way to remember it. Running the same sequence and taking every fourth step produces Saturday, Sunday, Monday and the rest in their familiar order, which is why the two schemes turn out to be the same idea applied at different scales.
What each attribution is read as adding
Under the Chaldean order Venus is treated as a softening influence on the opening of a water sign, read as sociable and drawn to comfort. Under the triplicity scheme the Moon rules both the sign and the face, and that doubling is read as concentrating the sign's own qualities rather than shading them.
Both readings are interpretation and should be taken as such. They describe what the tradition attaches to a position. Nothing about them is a claim regarding what a person born here will do, and choosing between the schemes is a matter of which lineage a practitioner follows.
How much of your chart this covers
Not much, and that is worth stating plainly. About one person in twelve shares a sun sign, and everyone born within a month of you in any year shares yours. The face narrows that to roughly a third of the sign, which is better and still not personal.
The Moon on this date may sit in either of two signs depending on the hour, and the ascendant may be any of the twelve, since a new sign meets the eastern horizon roughly every two hours. The widget above works your exact degree from your year, hour and birthplace and reports how far you were born from the nearest sign boundary.
The slow planets are the exception to that. Saturn, Uranus, Neptune and Pluto stay in a sign for years, so a birth date fixes them without any need for an hour. What they describe is a cohort born across the same stretch of years rather than one person within it.
Questions people ask about this
What sign is a 27 June birthday?
Cancer, in every year checked at noon between 1930 and 2035. The Sun sits close to six degrees along, so no birth hour brings it near either boundary.
Is the decan ruler Venus or the Moon?
Venus in the Chaldean face order and the Moon in the triplicity scheme. Both are traditional attributions for the same band, and which one applies depends on the system a source is using.
Why do the two schemes disagree?
They divide the zodiac by different logics. The Chaldean order walks the planets in speed sequence around all thirty six faces, while the triplicity scheme steps through the signs sharing an element.
Which scheme should I use?
Whichever your source uses, applied consistently. Mixing them within one reading produces contradictions that have nothing to do with the chart itself.
What degree of Cancer is this date?
Near six, ranging from about four and nine tenths to six and a third across the sampled century. The exact value comes from your year, hour and place of birth.
Does the decan matter more than the sign?
It narrows the description to a third of the sign, which is a real gain, but neither is personal. The Moon and the ascendant are what separate two people born on the same date.