What Is a Transit in Astrology?

The short definition

A transit is the current position of a planet, considered in relation to a position in your birth chart. Two charts are involved and only one of them moves. Your natal chart is a snapshot of a minute that has already happened, so it never changes. The transiting chart is the sky right now, and it changes continuously. Astrology reads the angles between the two.

That relationship is what makes daily astrology possible at all. A natal chart on its own has nothing to say about Tuesday — it describes a fixed configuration. Today's sky on its own has nothing to say about you, because it is the same sky for everyone alive. A transit is the intersection: this specific sky, meeting your specific chart, at an angle that is yours because your chart is.

How a transit is measured

Take a planet's position today, in degrees along the zodiac. Take a natal position from your chart — a planet, a house cusp, the Midheaven. Subtract. If the separation is close to one of a handful of significant angles, the two are said to be in aspect, and that is a transit worth reporting.

“Close to” is doing real work in that sentence. Aspects are allowed an orb — a tolerance of a few degrees either side of exact — and the closer to exact, the stronger the transit is considered. That is also why a transit has a shape over time rather than being a switch: it comes into orb, tightens toward exact, then separates. Astrologers call the first half applying and the second half separating, and applying is traditionally read as the more active of the two.

The family column is the classification the app sorts on. Harmonious aspects push a day's score up, challenging ones push it down, and conjunctions are treated as intense rather than good or bad — a merging whose flavour depends entirely on which two bodies are merging.

Fast transits and slow transits

The single most useful thing to know about transits is that they operate on wildly different timescales, because the planets do. A transit's duration is a direct consequence of its orbital period.

This is why a daily reading and a yearly forecast are not competing descriptions of the same thing. The Moon supplies most of the texture of any given day and is gone by tomorrow. Saturn supplies the background a whole year is set against, and does not care what day it is. A good daily reading has both in it, weighted appropriately, or it mistakes a passing mood for a turning point.

What each planet brings when it crosses a house

Below is DayLuck's own reading of each transiting planet as it crosses the tenth house — the house of career and public standing — so you can see the same house held still while the transiting body changes.

Moon

Public emotions through career

Sun

Career focus through public status

Mercury

Strategic thinking through career

Venus

Professional harmony through status

Mars

Career ambition through achievement

Jupiter

Career expansion through opportunity

Saturn

Career responsibility through authority

Uranus

Career innovation through disruption

Neptune

Career inspiration through vision

Pluto

Career transformation through destiny

A worked example

Two transits to the same chart, on two different days. The first is Jupiter in Cancer, crossing the eleventh house, trining that chart's second house of money. The second is Saturn in Aries, crossing the tenth house, squaring its seventh house of partnership.

The structure is identical and the tone is opposite, and the reason is one word in each sentence. A trine is in the harmonious family, so the verb is “flows easily into” and the advice is to act. A square is in the challenging family, so the verb is “puts pressure on” and the advice is to wait. Neither sentence predicts an event. Both describe a condition and suggest what to do with it, which is the most a transit reading honestly supports.

How DayLuck uses transits

Transits are the entire engine. DayLuck calculates your natal chart once, then for each day it computes the live positions of all ten bodies, finds every aspect they make to your natal placements, weights each one by aspect family, by how close to exact it is, and by how fast the transiting planet moves — then rolls the result into a score from +3 to −3 for Wealth, Love, Career and Social. The sentences you read under each score are those same transits written out one at a time.

Two things follow from that, and they are worth stating plainly. First, your scores are yours: the sky is shared, but the angles it makes to your chart are not, so two people reading DayLuck on the same morning routinely see different days. Second, a low score is a description of friction, not a forecast of misfortune — the advice attached to a challenging transit is always about timing and care, never about avoidance. Which placements the transits are landing on depends on your rising sign for the house layer and your Big Three for most of the rest.

Questions

How long does a transit last?

Anywhere from a few hours to a couple of years, entirely depending on which planet is doing the transiting. The Moon changes sign every two and a half days, so a Moon transit is a mood that has come and gone by tomorrow. Mars takes about two years to circle the zodiac, so its transits run for days. Saturn takes roughly twenty-nine years and Pluto around two hundred and forty-eight, so their transits to a single point in your chart can stay in effect for a year or more, and retrograde motion can bring the same one back two or three times. This is why daily astrology and "big year ahead" astrology are describing genuinely different things rather than the same thing at different volumes.

Is a transit the same as a retrograde?

No — a retrograde is a description of how a planet is moving, and a transit is a description of what it is meeting. Retrograde means a planet appears to move backwards against the zodiac from where we sit, which is an apparent effect of Earth overtaking it or being overtaken. A retrograde planet is still transiting; it is just transiting slowly and, often, over ground it has already covered. That is why a retrograde period is associated with revisiting things: the same transit forms, breaks and forms again over several months instead of passing once.