Secondary progressions: your chart's slow evolution
A day of sky for a year of life — the slowest and most-used symbolic clock in astrology.
3 min read · Published 30 August 2026
The short answer
Secondary progressions advance the chart one day for each year of life, so your chart at 40 is the sky as it looked 40 days after you were born. The progressed Sun moves about a degree a year, the progressed Moon about a degree a month. The events practitioners watch for are the progressed Sun changing sign, the progressed Moon changing sign, and the progressed New and Full Moon.
What moves, and how fast
| Factor | Progressed speed | Notable event |
|---|---|---|
| Sun | About 1° per year | Sign change roughly every 30 years |
| Moon | About 1° per month | Sign change every 2.5 years; full cycle in 27–28 years |
| Mercury | Variable; can turn retrograde | A progressed station lasts years |
| Venus | Variable; can turn retrograde | As above |
| Mars | About 0.5° per year | Sign change every 50–60 years |
| Jupiter and beyond | Barely moves | Effectively fixed within a lifetime |
Only the Sun, Moon, Mercury, Venus and Mars move enough to matter. The outer planets progress so little across a whole life that they are effectively part of the natal chart — which is why progressions are a technique about the personal planets.
The events worth watching
In descending order of significance
- Progressed Sun changes sign. Once every thirty years or so, and the single biggest event in the technique. Read as a shift in overall direction and self-expression.
- Progressed New Moon. When progressed Sun and Moon conjoin, beginning a new 29-and-a-half-year lunation cycle. Read as a fresh chapter.
- Progressed Full Moon. Roughly fifteen years later, when they oppose. Read as something begun becoming visible.
- Progressed Moon changes sign. Every two and a half years, marking emotional chapters — see progressed Moon cycles.
- A progressed planet turns retrograde or direct. Mercury or Venus stationing by progression is rare and lasts a long time.
Why a day for a year
The usual justification cites scriptural precedent — the day-for-a-year principle appears in Hebrew scripture — which is a historical explanation of where the idea came from rather than a reason it works.
A second argument notes that the Moon's cycle of about 27 to 28 days progressing to 27 to 28 years corresponds roughly to a human generational span, and that the Sun's degree-per-year gives a sign change at roughly the intervals people describe as life chapters.
That is post-hoc reasoning about a convention, not a derivation. The technique works with a symbolic ratio chosen because it produces movements on a human timescale, and being clear about that is more honest than dressing it as astronomy.
Reading them
Compare the progressed chart against the natal one, not against itself. A progressed planet contacting a natal placement is the standard technique.
Orbs are tight — typically one degree — because progressed factors move so slowly that a wider orb would last many years.
AsterNym computes your progressed Sun, Moon and lunation phase, along with the next progressed Sun ingress found by bisection, on your natal chart. Progressed angles are computed by the ascendant that would actually rise at your birthplace at the progressed moment, and the page names that method because others disagree.
Common questions
- How do secondary progressions work?
- Each day after your birth stands for one year of life, so your chart at forty is the sky as it looked forty days after you were born. The progressed Sun moves about a degree a year and the progressed Moon about a degree a month.
- What is the most important progression event?
- The progressed Sun changing sign, which happens roughly once every thirty years and is read as a shift in overall direction. After that, the progressed New Moon beginning a 29-and-a-half-year cycle, and the progressed Moon's sign changes every two and a half years.
- Why is it a day for a year?
- The ratio is a convention. It is usually justified by scriptural precedent for the day-for-a-year principle, and defended because it produces movements on a human timescale — but other ratios such as tertiary progressions exist, which shows the choice is conventional.
- Do outer planets progress?
- Barely. Jupiter and beyond move so little across an entire lifetime that they are effectively fixed, which is why secondary progressions are a technique concerning the Sun, Moon, Mercury, Venus and Mars.