Halfway through the first band
Each sign carries three decans of ten degrees. Five or six degrees of Aries falls near the centre of the first, far enough from zero that the opening degrees are behind it and far enough from ten that the second band is still several days away.
The Chaldean order gives this band to Mars, the same planet that rules Aries. Where most decans combine a sign ruler with a different decan ruler, this one repeats a single planet, which is why traditional writers treat it as the sign in its most concentrated form.
Ten degrees is roughly ten days of solar motion, so the band groups birthdays in a way that a thirty day sign does not. Someone born in the first week of Aries and someone born in the last share a sign and sit in different decans, which older sources treat as a real distinction rather than a rounding.
The reading and its limits
What the older sources say about a Mars decan in a Mars sign is a description of the band, phrased in the vocabulary of the tradition. It is not a measurement and it does not carry a prediction, and a birthday page that presents it as a personality report has moved from one kind of claim to another without saying so.
The useful separation is this. The degree and the decan can be checked against any ephemeris and will agree. The character attached to the band comes from a chain of texts and cannot be checked at all. Both are worth reading, and it is fair to hold them to different standards.
Why a century fits in a degree and a half
Across 1930 to 2035 the noon position on this date has stayed between about 4.9 and 6.3 degrees. That narrowness comes from the leap year rule rather than from anything about the date.
A common year is roughly a quarter of a day shorter than the Sun's circuit, so the position gains about a quarter of a degree annually, and the extra day in February takes back almost exactly four years of gains. The result oscillates instead of drifting. Which end of the oscillation your own birth falls on depends on your year, which the widget above resolves along with your exact degree.
There is a slower correction buried in the same arithmetic, since the Gregorian calendar skips three leap days every four hundred years to keep the average year close to the tropical one. That refinement matters over millennia and not over the span of a birthday page, and any exact figure should come from an ephemeris rather than from the approximation.
The rest of the chart
The Moon moves roughly thirteen degrees a day and will be in one of two signs on this date, sometimes one of three. The hour decides, and the date supplies nothing.
The Ascendant is a matter of the clock and the birthplace. It cycles through all twelve signs daily, which makes it the most individual of the common placements and the one a birthday can never reach.
Mercury and Venus fall somewhere in between. Both stay near the Sun, so this date puts Mercury within about a sign of Aries and Venus within two. That is a genuine narrowing from the date alone, though the exact positions still need a year to pin down.
Questions people ask about this
What sign is 26 March?
Aries, in every year from 1930 to 2035 measured at noon. The equinox falls on 20 or 21 March across that range, so the Sun has been in the sign for five or six days by this date.
Where in Aries does it fall?
Between about five and six degrees, near the middle of the first decan. The widget above computes the exact figure from your year, hour and birthplace.
What is a decan ruler?
A planet assigned to a ten degree band inside a sign. The Chaldean order takes the sequence used for the planetary hours and runs it through the thirty six bands, which puts Mars on the first decan of Aries.
Is the middle of a decan more significant?
Some traditional writers treat the central degrees of a band as its clearest expression and the edges as transitional. That is a convention within the tradition rather than a measurable difference.
Does the year of birth change the sign?
Not on this date. The year moves the degree by about a degree and a third at most, which is nowhere near enough to reach a boundary.
What would a birth time tell me?
The rising sign, the house cusps and the Moon's exact degree, plus a solar degree accurate to a fraction rather than to the nearest degree.