The exact position, not just the sign
Taken at noon in every year from 1930 to 2035, a 28 April Sun falls between seven point three and eight point seven degrees of Taurus. That is a spread of about a degree and a half across more than a century, which is small enough that the position can be described as near eight degrees without much loss.
A degree of solar longitude is worth about a day of the calendar here, so knowing the figure to a fraction is a real gain over knowing the sign. The reason it holds so steady is the leap year cycle. The tropical year runs a little under three hundred and sixty five and a quarter days, so the Sun arrives at each calendar date roughly six hours later each year until February gains a day and pulls it back. The drift never accumulates, and the date keeps its place in the orbit.
Inside the first decan, where the rulers disagree
Each sign divides into three bands of ten degrees called decans or faces. Eight degrees puts this birthday in the first of the Taurus decans, from zero to ten, with room to spare at both ends. No year in the sampled range moves it out.
The Chaldean order runs Mars, Sun, Venus, Mercury, Moon, Saturn, Jupiter, repeating from the start of Aries without a break. Counted that way, the first decan of Taurus lands on Mercury. The triplicity scheme instead gives each decan of a sign to a sign of the same element in order, so the earth decans go Taurus, Virgo, Capricorn, and this one belongs to Taurus and therefore to Venus. Both are traditional, and a decan ruler quoted for this birthday without naming the scheme is quoting half an answer.
Neither count is a later invention. The Chaldean sequence is the older of the two in surviving texts and the triplicity arrangement became the more common one in medieval practice, so both turn up in reputable sources and neither can be dismissed.
What the tradition reads into it
Taurus is fixed earth under Venus, and the older texts read it as steady, sensory and reluctant to be hurried. The first decan is where the sign is described as most itself, since the Sun has just left the fire of Aries and settled.
Add Mercury from the Chaldean count and the reading picks up a quicker, more verbal edge on an otherwise slow sign. Add Venus from the triplicity count and the reading doubles down on the sign's own character instead. These are interpretations rather than measurements, and it is worth holding them as such.
What 28 April leaves entirely open
The Moon crosses a sign in about two and a half days, so a birth on this date can carry a Moon in either of two signs, and occasionally three if the change falls near midnight. The date on its own cannot tell you which.
The rising sign is looser still. The whole zodiac passes the eastern horizon every day, so any of the twelve can be rising on 28 April depending on the hour and the latitude of the birthplace. That single placement usually shapes a chart reading more than the Sun does, which puts the sun sign closer to the least personal part of a chart than the most. Everyone born within about a month of you shares it. The widget above takes your year and birthplace, returns the exact solar degree rather than a rounded one, and reports how far the birth stood from the nearest sign boundary.
Questions people ask about this
Is 28 April always Taurus?
Yes, at noon in every year from 1930 to 2035. The date sits well clear of both the Aries boundary behind it and the Gemini boundary ahead, so no plausible birth year or hour changes the sun sign.
What degree of Taurus is a 28 April Sun?
Between roughly seven and nine degrees, depending on the year and the hour. The widget above narrows that to a precise figure once it has your birth details.
Which decan does this birthday fall in?
The first decan of Taurus, covering zero to ten degrees. The Sun stays inside it on this date in every year checked, so there is no year in which the answer changes.
Is the decan ruler Mercury or Venus?
It depends on the scheme. The Chaldean order of faces gives Mercury, while the triplicity scheme gives Venus. Neither is a mistake, and a source that names one without saying which method it used has simply left out the important part.
Does a 28 April birthday tell me my Moon sign?
No. The Moon moves through a sign in about two and a half days, so the date narrows it to two possibilities at best. The birth hour is needed to settle it.
Why does my degree matter if the sign is fixed?
Because aspects and house cusps are measured in degrees, not signs. Two people born a week apart share a sun sign but their Suns make quite different contacts with the rest of a chart.