A body facing its own starting point
The opposition is the plainest geometry in the whole cycle. Saturn has crossed half the ecliptic since your birth, so from Earth it appears in the sign and degree exactly opposite the one it occupied then. There is nothing hidden in it: it is a position, and it can be looked up.
Because the lap runs about twenty nine and a half years, half of it runs about fourteen and three quarters. That gives the familiar figures of fourteen or fifteen for the first opposition and forty three to forty five for the second, with the pattern continuing at roughly thirty year intervals after that.
The widget above finds the crossings by tracking Saturn's real longitude against your natal degree, which is why the dates it returns are yours rather than a rounded age.
Why the age moves by a year or more
Saturn does not travel at a constant rate. Its orbit is an ellipse, and a body in an elliptical orbit speeds up near the Sun and slows down away from it. Half a lap therefore takes less time from some starting degrees than from others.
In practice the first opposition lands anywhere from about thirteen and a half to nearly sixteen, and the second across a spread of roughly three years around forty four. Neither figure is a rule, and the further into the cycle you look the more the difference accumulates. This is the same mechanism that stretches the Saturn return across twenty eight to thirty one, seen at the halfway mark instead.
How many times it happens
Saturn turns retrograde for around four and a half months every year, and the opposition to natal Saturn very often falls near one of those stations. When it does, Saturn reaches the opposite degree, reverses back across it and then crosses it a third time going forward. That triple pass typically stretches from nine months to about a year.
When the timing falls clear of a station there is a single crossing instead, over in a matter of days. The tradition treats the whole span as the transit either way, so the useful figure is not one date but the run from first pass to last. The calculator above prints each pass so you can see which of the two cases applies to you.
What the tradition reads into the halfway mark
Astrological convention treats an opposition as two positions in full view of each other, and a Saturn opposition to natal Saturn as the point where what you have built so far is set against what you set out to build. The teenage version is traditionally linked to the first real push against authority and the mid forties version to the stretch commonly labelled a midlife reckoning. The promise attached is a clear look at an arrangement that has been running unexamined. The difficulty attached is that the view is not always welcome. Both of those are conventions of the tradition rather than measured effects, and nothing here predicts an event in your life.
The house holding your natal Saturn, and the opposite house where the transit falls, are what make any interpretation specific to your chart. Houses require a birth time. The dates do not, since Saturn's degree barely shifts across a single day.
Questions people ask about this
At what age is Saturn opposite Saturn?
The first falls near fourteen or fifteen and the second near forty four. Both carry a spread of a year or more either side, because Saturn's speed varies across its elliptical orbit.
How is it different from the Saturn return?
The return is Saturn back at its birth degree, the end of a lap. The opposition is the halfway mark, with Saturn directly across the zodiac from where it began.
Does the opposition repeat?
Yes, once in every lap, so roughly every twenty nine and a half years. After the mid forties the next arrives in the early seventies.
Why do I get three dates?
Because the aspect fell near one of Saturn's retrograde stations, so it was crossed forwards, backwards and forwards again. The span from first to last is usually nine months to a year.
Is a birth time required?
Only for the houses. The dates are reliable without one, but the house placement is what turns a general description into a reading tied to your own chart.
Is this the midlife crisis transit?
That label is usually attached to the Uranus opposition near forty, and sometimes to this one as well. It is a convention of interpretation, and this page makes no claim about what will happen to you.