Ninety degrees, twice a year
The square is 90 degrees of ecliptic separation, and the orb here is seven degrees, so anything between about 83 and 97 degrees counts, in either direction. The Sun moves roughly a degree a day, so a square holds for about a fortnight on each side of the exact figure.
The Sun squares Saturn twice in each cycle of about 378 days, once before the opposition and once after. That makes it slightly more frequent than annual, and because both windows are a couple of weeks wide, a fair share of birth charts contain it.
Squares connect signs of the same modality, cardinal, fixed or mutable, but different elements. That is where the friction is located in the traditional model: two bodies wanting to operate at the same tempo and in incompatible terms.
What the friction is said to do
The Sun is the conscious sense of self, the thing a person is trying to be. Saturn is the limit that does not negotiate: time, rules, the absence of resources, the standard someone else set. In a square these two are close enough to obstruct and too far apart to blend.
The description that recurs across sources is delayed confidence. Recognition arrives later than it does for other people, first attempts meet a wall, and the person's own estimate of themselves lags behind the evidence for a long time. In older texts this is written up bluntly as misfortune. Modern practitioners are more likely to describe a chart that develops competence because it could not rely on charm.
The failure mode named in most accounts is not laziness but the opposite: a habit of proving oneself that does not switch off once the point has been made. The tradition also links the aspect to authority figures met early, and to a standard internalised from one of them that keeps being applied long after that person has gone.
Modality, dignity and where it lands
Since a square joins signs of one modality, the modality sets the pace. A cardinal square, Sun in Aries with Saturn in Capricorn for instance, is the version that keeps starting things. A fixed square is the version that digs in. A mutable square scatters the tension across more areas and is often read as less concentrated but harder to pin down.
Dignity matters here more than in most aspects because the two bodies have such clear traditional placements. A Saturn in Capricorn or Aquarius square a Sun in Aries or Libra gives the restrictive end the stronger footing. Reverse the strengths and the same angle reads as a Sun that pushes back harder.
Houses tell you what is actually being obstructed. The tenth and first pairing is the one written about most, since it puts standing and self presentation in direct conflict. A square between the fifth and the second is a much narrower matter and rarely described as defining.
Timing, orb and the check above
Saturn takes about twenty nine and a half years to return to its birth position, and it squares that position at roughly seven and fourteen and twenty two years of age. Anyone with a natal Sun square Saturn gets those transits landing on an already active configuration, which is why practitioners often read the mid twenties as a decisive stretch for this aspect.
Orb decides how much of the description to take seriously. Under two degrees it is normally read as a central feature. Between four and seven it is a contributing factor, easily overridden by a close trine or conjunction to either body. Out of sign squares, where the degree separation qualifies but the modality relationship does not, are usually read as weaker.
The widget above gives you the separation in degrees along with both signs and houses, which is the information a general article cannot know.
Questions people ask about this
How often does the Sun square Saturn?
Twice in each Sun to Saturn cycle of about 378 days, once on each side of their opposition. Each square stays within the seven degree orb for roughly a fortnight either side of exact, so it is a fairly common birth aspect.
Does Sun square Saturn mean a hard life?
No. The tradition reads it as effort meeting resistance and as recognition arriving later than expected, which is a description of a pattern rather than a prediction of an outcome. Sign, dignity, house and the rest of the chart all change what it amounts to.
What orb should I use?
Seven degrees for a square, covering separations of roughly 83 to 97 degrees. The Sun's motion of about a degree a day means that window is around two weeks wide on either side of the exact aspect.
Which is stronger, the square or the opposition?
Neither is automatically stronger. The square has the tighter orb and is generally described as producing action through friction, while the opposition has a wider orb and is described as producing awareness and stalemate. Which is more prominent in a chart depends mostly on exactness.
How does the Saturn return relate to this?
Saturn returns to its natal degree at around twenty nine and again near fifty eight, and it squares that degree at roughly seven, fourteen and twenty two. With a natal Sun square Saturn these transits activate an existing configuration rather than arriving on empty ground.
Can other aspects offset it?
Yes. A close trine or sextile from Jupiter or Venus to either body is generally read as easing the description, and a strong, well placed Sun does the same. A T-square, where a third body squares both, does the reverse and makes the pattern more central.