A century in a degree and a half
People expect the sky to be less tidy than that. The narrowness comes from the calendar rather than from the orbit. A year of three hundred and sixty five whole days runs about six hours short of the tropical year, so the Sun reaches a given point a quarter of a day later each time, which shows up as roughly a quarter of a degree of extra travel on a fixed date.
The leap day removes the accumulated shortfall by pushing the calendar forward a whole day, which drops the solar position back by nearly a degree. Repeat that cycle and the position oscillates around a mean rather than drifting. The Gregorian rule about century years trims the last small error, which is why the figure holds over long spans.
Where that position sits inside Pisces
Thirteen degrees is inside the second decan, the middle ten degree band of the sign, which runs from ten to twenty degrees. That places a 3 March birth clear of both decan boundaries, which is not true of every date in this stretch of the calendar.
The Chaldean table gives this band to Jupiter. Since Jupiter is also the traditional ruler of Pisces, a Sun here is described in older sources as being in the least modified third of the sign, generous and wide rather than contained. It is a reading rather than a result, and it should be held as one.
Sitting clear of a boundary also means the decan holds regardless of the birth hour or the time zone applied. That is not true of every date in the calendar, and it is a small piece of certainty worth having.
What the sign label leaves out
The word Pisces covers roughly thirty days of birthdays. Everyone born inside that window shares it, which makes it the broadest and least individual part of a chart. The degree, the decan and the house the Sun falls in are what start to separate one chart from another.
The Moon, meanwhile, may sit in two or three different signs across a single 3 March depending on the hour, and the rising sign can be any of the twelve. Neither follows from the calendar date in any way.
It is a matter of scale rather than importance. The sun sign is a broad statement that happens to be correct, and the finer layers are what turn a shared description into a specific one.
Getting your own figure
The range above is a summary of noon positions, not a personal result. Your own degree depends on your birth year, on the hour and on the longitude of your birthplace, and the widget above computes it from those three inputs.
It also reports how far your Sun stood from the nearest sign boundary. On this date that distance is wide in every direction, so the sun sign is settled whatever else is missing from your birth record.
If the hour is lost, the usual approach is to cast for noon, keep the Sun and the slow moving planets, and treat the Moon and everything angular as unresolved rather than assumed.
Questions people ask about this
What is the sun sign for 3 March?
Pisces. The Sun entered the sign around the middle of February and does not leave for Aries until around 20 March, so this date is never in question.
What solar degree does 3 March give?
Between roughly twelve and thirteen point four degrees of Pisces at noon, across all years from 1930 to 2035.
Which decan is 3 March in?
The second decan of Pisces, which runs from ten to twenty degrees and takes Jupiter as its Chaldean ruler. This date sits safely inside it rather than near either edge.
Why does the solar position hardly change between years?
Because the leap year cycle keeps the calendar and the orbit aligned. The forward drift of common years is cancelled by the backward step of each leap day.
Do I share a chart with anyone born on the same date?
Only the Sun, and only approximately. The Moon and the rising sign depend on the hour and the birthplace, so two charts from the same date can look quite different.
Does the decan ruler replace the sign ruler?
No. It sits alongside it as a finer layer. Pisces keeps Jupiter traditionally and Neptune in modern practice, and the decan adds an extra planetary flavour to a specific ten degree band.