The figure and the range
On 26 January the Sun has been between about 5.4 and 6.8 degrees of Aquarius at noon across that whole span. Someone born on this date in 1934 and someone born in 2031 have Suns closer together than most people would guess a century could allow.
This is the part almost no birthday page publishes, and it is the part that makes the position checkable. A sign is a thirty degree band and tells you which band. A degree tells you where in it, which is what aspects and house placement are actually measured against.
Why the leap cycle holds it there
The tropical year is close to 365.2422 days, so an ordinary calendar year of 365 days runs short and the Sun ends up about a quarter of a degree further along at the same clock time the following year. Three ordinary years accumulate roughly three quarters of a degree of that drift.
February then gains a leap day, the calendar overshoots by nearly a full day, and the position drops back by close to a degree. What remains is a small sawtooth around a fixed value rather than a steady march in one direction. Your own year decides where in that sawtooth you land.
The Gregorian reform of 1582 is what makes this work. Dropping three leap days every four hundred years brings the average calendar year to 365.2425 days, within half a minute of the tropical year, so the drift the Julian calendar accumulated no longer builds up.
What does not shift it either
Precession is often raised at this point. It genuinely moves the constellations against the signs at roughly one degree every seventy two years, but the tropical zodiac used here is defined from the March equinox rather than from the stars, so the tropical degrees and the calendar dates are untouched by it.
Sidereal astrology, used in the Indian tradition, does track the stars and so gives a different figure and often a different sign. That is a difference of definition rather than of accuracy, and it matters only that you know which framework a given position was calculated in.
The decan, and what still needs an hour
Six degrees falls in the first decan of Aquarius, the band from zero to ten, which the Chaldean order assigns to Venus while Saturn and Uranus rule the sign. That is a plain consequence of the measured longitude rather than a separate claim.
The Moon is a different matter. It moves around thirteen degrees a day and can be in more than one sign on a given 26 January, so it needs the year and the hour. The ascendant needs the hour and the birthplace and has no relationship to the date at all. The widget above supplies the exact solar figure and the margin to the nearest boundary.
Mercury and Venus are loosely pinned by the date because neither strays far from the Sun, Mercury within about a sign of Aquarius and Venus within two. Jupiter and Saturn depend on the birth year instead, so across a century this date has seen them in every sign.
Questions people ask about this
What degree is the Sun on 26 January?
Between about five and seven degrees of Aquarius, depending on the year and the hour. The widget above computes the exact value from your own birth details.
Why does the degree barely change across a century?
Because the leap year cycle keeps the calendar in step with the orbit. The position drifts forward by about a quarter of a degree each ordinary year and the leap day pulls it back.
Does precession change my sun sign?
Not in tropical astrology, which defines the signs from the equinox rather than the stars. Sidereal astrology does track the stars and will often give a different sign for the same birth.
Is 26 January ever Capricorn?
No. The Sun enters Aquarius on 19, 20 or 21 January, so by the twenty sixth it is five to seven degrees inside the sign in every year.
Which decan does this birthday fall in?
The first decan of Aquarius, zero to ten degrees, ruled by Venus in the Chaldean sequence. Saturn and Uranus remain the rulers of the sign itself.
Why does the degree matter at all?
Because aspects are measured in degrees and house placement follows the degree. Sign membership does not change within a sign, but almost everything else about a placement does.