Mars in the 4th house puts the planet of heat and conflict in the room of home, family and roots. Most guides stop at a hot temper behind closed doors. We asked a plainer question first. When are people born with it? Most years, the answer is late at night. But for a few weeks every two years, the answer flips to late morning and noon.
Those few weeks are the weeks when Mars moves backward in the sky. Astrologers call that motion retrograde. So the hour of birth and the backward loop of Mars are tied together here. Born between 10 a.m. and 1 p.m. with Mars in the 4th house, your Mars is retrograde more than nine times in ten. Born between 5 p.m. and 6 a.m., it is almost never retrograde.
The hospital clock then does the rest. On real U.S. birth hours, one Mars in the 4th house in eight is retrograde. The sky alone would give about one in eleven. For babies born by C-section, it is almost one in five. This guide shows how we counted, then what the old and new astrologers say Mars does in this room.
The room at the bottom of the sky
A birth chart is a map of the sky at the moment you were born. The houses are twelve slices of that sky. Each slice covers one part of life. The 4th house covers home, parents, land, roots and the private self. Our guide to 4th house astrology tells the full story of the room.
The 4th house starts at the lowest point of the sky, straight under your feet. That point has a Latin name, the Imum Coeli, or IC. It means the bottom of the sky. The Sun reaches it at midnight, sun time. So the 4th house is the midnight zone of a chart.
The IC is one of the four angles, the pivots of a chart. The other three are the eastern horizon, the western horizon and the top of the sky. The Greek authors read a planet near an angle as strong and busy. So Mars in the 4th house is not a quiet guest. It sits on a pivot, in the most private room of the chart.
Mars in the 4th house is about to reach its lowest point
The sky turns from east to west once a day. A planet rises in the east, crosses the top of the sky, and sets in the west. After it sets, it moves through the 6th house, then the 5th, then the 4th. At the end of the 4th house, it reaches the IC, its lowest point. Then it climbs again through the 3rd, 2nd and 1st houses, and rises.
So Mars in the 4th house means Mars had set some hours before your birth. It was under the ground, on the far side of the Earth. And it was in the last stretch before its lowest point. In round terms, a planet sits in the 4th house for about two hours before it reaches the IC.
We checked this on two real days in New York. On the night of 9 January 2026, the Placidus 4th house window closed at 12:03 a.m. Eastern Standard Time. Mars reached its lowest point below New York at 12:03 a.m. On 19 February 2027, the window closes at 12:10 p.m. Mars reaches its lowest point at 12:16 p.m. The small gap comes from the tilt of the Mars orbit, which lifts Mars a little off the Sun’s path.
Midnight or noon: the Mars cycle picks the hour
Mars does not keep one hour. It moves around the sky compared with the Sun. The Earth laps Mars once every 780 days on average. That lap is the synodic cycle, which means the cycle of Mars as seen from Earth. Our guide to Mars in the 1st house walks through that cycle stage by stage.
Two stages set the extremes. At conjunction, Mars sits behind the Sun and keeps the Sun’s hours. It reaches its lowest point near midnight. So it sits in the 4th house from about 10 p.m. to midnight, sun time. At opposition, Mars sits across the sky from the Earth’s view of the Sun. It reaches its lowest point near noon. So it sits in the 4th house in the late morning, from about 10 a.m. to noon, sun time.
Now the key fact. Mars spends most of its cycle near the Sun, on the far side of it. In our count from 1940 to 2030, Mars sat within 60 degrees of the Sun 52.9 percent of the time. It sat within 30 degrees of the opposition point only 5.9 percent of the time. So most years, Mars in the 4th house is a late night placement. The noon version is short and rare.
The clock, hour by hour
Here is the chance of Mars in the 4th house for each hour on the clock. It covers births in 36 large U.S. metro areas, weighted by their size. It uses Placidus houses, the system most U.S. charts use. The hours are local clock time, with daylight saving time applied. Every date from 1940 to 2030 counts the same.
| Birth hour on the clock | Chance of Mars in the 4th house. |
|---|---|
| Midnight to 1 a.m. | 13.2 percent, about 1 in 8. |
| 2 a.m. to 3 a.m. | 12.5 percent, about 1 in 8. |
| 4 a.m. to 5 a.m. | 10.4 percent, about 1 in 10. |
| 6 a.m. to 7 a.m. | 6.9 percent, about 1 in 14. |
| 8 a.m. to 9 a.m. | 4.3 percent, about 1 in 23. |
| 10 a.m. to 11 a.m. | 3.1 percent, about 1 in 32. |
| 11 a.m. to noon. | 2.9 percent, about 1 in 34. |
| 2 p.m. to 3 p.m. | 3.9 percent, about 1 in 26. |
| 4 p.m. to 5 p.m. | 6.2 percent, about 1 in 16. |
| 6 p.m. to 7 p.m. | 9.5 percent, about 1 in 11. |
| 8 p.m. to 9 p.m. | 12.4 percent, about 1 in 8. |
| 11 p.m. to midnight. | 13.5 percent, about 1 in 7. |
The high point is the 11 p.m. hour. The low point is the 11 a.m. hour. The top is more than four times the bottom. The shape is the Sun’s own 4th house hours, spread out by a few hours on each side.
The clock time here is not sun time. In summer, daylight saving time moves the clock one hour ahead of the sky. Each time zone is also wide, so sun time drifts from clock time by up to an hour or so from east to west. That is why the peak sits on both sides of midnight and not on one single hour.
Real birth hours make it rarer
Babies are not born evenly across the day. Hospitals book planned births, and those land in working hours. To test this, we used the CDC natality file 2024. It is the full U.S. birth record for that year, with 3,638,436 births, nearly all with a time of birth. The busiest hour is 8 a.m., with 6.27 percent of all births. The small hours are the quietest, near 3 percent each. The noon hour is the second peak, with 5.65 percent.
C-section births, where the baby is delivered by surgery, made up about one U.S. birth in three in that file. They peak hard at 8 a.m., with 11.4 percent of them in that one hour. They are rare in the small hours, near 2 percent an hour.
So we ran the count twice. First, every clock minute had the same weight. Then each minute was weighted by its real share in the CDC file.
| Birth hours used | Placidus houses | Whole sign houses. |
|---|---|---|
| Every hour equal | 8.23 percent | 8.18 percent. |
| Real U.S. birth hours, all days | 7.52 percent | 7.43 percent. |
| Real hours, weekdays | 7.40 percent | 7.30 percent. |
| Real hours, weekends | 7.95 percent | 7.91 percent. |
| C-section births | 6.51 percent | 6.50 percent. |
| Births after labor was started with drugs | 8.02 percent | 7.79 percent. |
A plain chance of one in twelve is 8.33 percent. On a U.S. hospital clock, Mars in the 4th house runs below that, at 7.52 percent under Placidus. That is about one birth in thirteen. C-section babies come last, at 6.51 percent, or about one in fifteen. Most years, their 8 a.m. peak lands far from the late night window of this placement.
What the Mars cycle does to your odds
With every hour equal, the stage of the Mars cycle makes almost no difference. The share stays between 8.0 and 8.4 percent under Placidus at every stage. The 4th house moves around the clock, but it always takes about the same slice of the day.
With real birth hours, the stage makes a big difference. Here are the results in time order, starting when Mars passes behind the Sun. The days column gives the length of each stage in an average cycle of 780 days.
| Stage of the Mars cycle | Days in the stage | When Mars is in the 4th house | All real U.S. births | C-section births only. |
|---|---|---|---|---|
| Just after Mars passes behind the Sun | About 106 days | 10 p.m. to midnight | 7.2 percent | 5.5 percent. |
| Morning sky, 30 to 90 degrees from the Sun | About 178 days | 6 p.m. to 10 p.m. | 7.9 percent | 6.5 percent. |
| Morning sky, 90 to 150 degrees from the Sun | About 82 days | 1 p.m. to 6 p.m. | 9.4 percent | 8.8 percent. |
| Around opposition, Mars retrograde | About 46 days | 10 a.m. to 2 p.m. | 10.1 percent | 12.9 percent. |
| Evening sky, 90 to 150 degrees from the Sun | About 82 days | 6 a.m. to 10 a.m. | 8.4 percent | 10.9 percent. |
| Evening sky, 30 to 90 degrees from the Sun | About 179 days | 2 a.m. to 6 a.m. | 6.0 percent | 3.7 percent. |
| Mars closing in on the Sun again | About 106 days | Midnight to 2 a.m. | 6.5 percent | 4.4 percent. |
The weeks around opposition are rich in Mars in the 4th births. Then its window sits in the late morning and the noon hour, the second busiest stretch of the hospital day. About one C-section baby in eight gets it then.
The richest stretch of all for C-sections comes a little later. Some five weeks after opposition, near the end of the loop, the window slides back to 8 a.m., the peak hour of planned surgery. In that stretch, up to 17.0 percent of C-section babies get Mars in the 4th house, about one in six.
The long stages near the Sun push the other way. There, the window falls in the late evening and the small hours. Few planned births happen then. This is why the full count lands below one in twelve.
Why one Mars in the 4th in eight is retrograde
Retrograde means Mars looks as if it moves backward against the stars. It is not a real change of course. The Earth, on its faster inside track, passes Mars. For a few weeks, Mars seems to slide back. This loop always sits around opposition. Mars turns retrograde four to six weeks before opposition and turns direct again four to six weeks after it.
From 1940 to 2030, Mars was retrograde 9.4 percent of the time, about one day in eleven. Those are the very weeks when its 4th house window moves into hospital hours. So we counted how many Mars in the 4th house charts carry a retrograde Mars.
| Birth hours used | Retrograde, Placidus | Retrograde, whole sign. |
|---|---|---|
| Share of all days with Mars retrograde | 9.4 percent | 9.4 percent. |
| Every hour equal | 9.2 percent | 9.1 percent. |
| Real U.S. birth hours, all days | 12.6 percent | 12.3 percent. |
| Real hours, weekdays | 13.1 percent | 12.9 percent. |
| Real hours, weekends | 10.7 percent | 10.4 percent. |
| C-section births | 18.7 percent | 17.2 percent. |
With every hour equal, the backward loop shows up at its plain rate. With real birth hours, one Mars in the 4th house in eight is retrograde. For C-section babies, the rate is almost one in five, twice the sky’s own rate.
The reason is the clock. A retrograde Mars reaches its lowest point in daylight, and the busy ward is open. A direct Mars far from opposition reaches it at night, and the ward is quiet. Weekends show the effect least, because fewer surgeries are booked then.
Born near noon, Mars in the 4th house is retrograde
The link also works the other way. If you know your birth hour and you have Mars in the 4th house, the hour tells you whether your Mars is retrograde. Here is the share of Mars in the 4th house charts with a retrograde Mars, by clock hour. It uses Placidus houses and every date from 1940 to 2030.
| Birth hour on the clock | Mars in the 4th house that is retrograde. |
|---|---|
| 5 p.m. to 7 a.m. | Almost none, 1 in 1,000 or fewer. |
| 7 a.m. to 8 a.m. | 4.9 percent, about 1 in 20. |
| 8 a.m. to 9 a.m. | 29.4 percent, about 3 in 10. |
| 9 a.m. to 10 a.m. | 68.8 percent, about 7 in 10. |
| 10 a.m. to 11 a.m. | 94.1 percent, more than 9 in 10. |
| 11 a.m. to 1 p.m. | 99 percent or more, nearly all. |
| 1 p.m. to 2 p.m. | 86.4 percent, about 6 in 7. |
| 2 p.m. to 3 p.m. | 50.0 percent, 1 in 2. |
| 3 p.m. to 4 p.m. | 14.8 percent, about 1 in 7. |
| 4 p.m. to 5 p.m. | 1.6 percent, about 1 in 60. |
A Mars in the 4th house at noon has to be close to opposition, and Mars near opposition is retrograde. A Mars in the 4th house at midnight has to be close to the Sun, and Mars near the Sun always moves forward. So the clock settles the question for most charts.
The recent retrograde loops, in New York time
Here are the dates of the recent loops. The station is the day Mars seems to stop and turn. The dates are in New York time. Births inside these dates carry a retrograde Mars.
| Mars turns retrograde | Opposition | Mars turns direct. |
|---|---|---|
| 26 June 2018 | 27 July 2018 | 27 August 2018. |
| 9 September 2020 | 13 October 2020 | 13 November 2020. |
| 30 October 2022 | 8 December 2022 | 12 January 2023. |
| 6 December 2024 | 15 January 2025 | 23 February 2025. |
| 10 January 2027 | 19 February 2027 | 1 April 2027. |
Time zones move some of these dates. In 2020, Mars turned direct at 12:36 a.m. on 14 November in Universal Time. In New York, that was still the evening of 13 November. The same thing happened in 2025, when Mars turned direct on the evening of 23 February, New York time.
Four real days in New York
To make this concrete, we computed the exact clock window for a birth in New York City on four dates. We used Placidus houses and New York clock time.
On 9 January 2026, Mars was behind the Sun. Mars sat in the 4th house from 9:36 p.m. to 12:03 a.m. the next day, Eastern Standard Time. It was a night chart, and Mars was direct.
On 25 September 2026, Mars was in the morning sky, 64 degrees from the Sun. The window ran from 7:06 p.m. to 8:41 p.m. Eastern Daylight Time. That is dinner time, with the Sun just set.
On 19 February 2027, Mars reaches opposition. The window runs from 10:24 a.m. to 12:10 p.m. Eastern Standard Time. That is a day chart, in busy ward hours, and Mars is retrograde.
On 25 March 2027, Mars is still retrograde, a week before it turns. The window runs from 8:37 a.m. to 10:20 a.m. Eastern Daylight Time. That is the peak of the planned surgery day.
Each window lasts about two hours. That is why the house needs an exact birth time. A time rounded to the hour can move Mars in or out of the 4th house.
Two house systems, two answers
Astrologers split the sky into houses in more than one way. In whole sign houses, each house is one full sign. Count three signs on from your rising sign, and that sign is your 4th house. This is the oldest system on record. Chris Brennan argues that it was the standard method of the Greek authors, and Demetra George uses it in her books on the old tradition.
In Placidus houses, each house is a slice of time. Each point of the sky takes the same share of its night arc to cross each house below the horizon. The IC always opens the 4th house. Most U.S. software uses Placidus by default.
The two systems do not always agree. On 9 January 2026 in New York, Placidus puts Mars in the 4th house from 9:36 p.m. to 12:03 a.m. Whole sign puts it there from 10:38 p.m. to 1:09 a.m. On opposition day in 2027, the two windows are 10:24 a.m. to 12:10 p.m. and 10:37 a.m. to 12:31 p.m. If your chart shows Mars in the 3rd or the 5th house, the house system is the first thing to check.
The totals come out close: 7.52 percent under Placidus and 7.43 percent under whole sign, with real hours. The retrograde share holds in both systems too.
What the old texts say about Mars here
Ptolemy, in the Tetrabiblos, calls Mars one of the two malefic planets, which means a planet that brings harm when it is out of place. He sorts the planets into two teams, one of the day and one of the night. Modern authors call this sect. Mars belongs to the night team, and the tradition holds that it does less harm in a night chart.
Vettius Valens, a working astrologer of the second century, calls the bottom angle the place of the foundation. William Lilly gives it the father, lands, houses, inheritance and what he calls the end of all things. Firmicus Maternus, in book three of his Mathesis, reads Mars at the bottom of the sky as hard on the parents and on the family estate.
Our count gives that rule a new weight. With every hour equal, 71.4 percent of Mars in the 4th house charts are night charts. With real U.S. birth hours, 64.4 percent are. Among C-section babies, only 53.5 percent are. The retrograde Mars in the 4th house is almost always a day chart, because it falls near noon.
William Lilly, in Christian Astrology in 1647, gives a table of accidental strength, a score for how well a planet is placed in a given chart. A planet in the 4th house gets four points, the same as the 7th and the 11th. The 1st and the 10th get five. But a retrograde planet loses five points. So for Lilly, a retrograde Mars in the 4th house gives back more than its angle earned. Our count says that the hospital clock hands out that weaker version more than the sky alone would.
These are judgments from a symbolic craft, not measured facts. We give them so you know where the claims you read come from.
What modern astrologers read into it
Modern writers move the focus from events to the inner life. Stephen Arroyo reads Mars as the way you go after what you want. In the 4th house, the want is a safe base of your own. You fight for it, build it and guard it.
Liz Greene treats Mars as the urge to stand apart as your own person. In the room of the family, that urge has to push against the people who raised you. Robert Hand reads houses as fields of life where a planet acts. Mars in the field of home acts through repairs, moves, building work and family quarrels.
A retrograde Mars adds a twist in modern reading. The drive turns inward before it turns outward. Many modern writers read it as anger that is held in, then let out in private. In the 4th house, that private place is home itself.
How it can show up in a life
Every chart is more than one placement. Read these as patterns to test, not verdicts.
- A home you build yourself. You fix, paint and move walls rather than wait for help.
- A fierce guard on family. Criticism of your people lands as an attack on you.
- Heat behind the door. The calm you show in public can break at home.
- Moves and new starts. You leave a house or a town when it stops feeling like yours.
- A strong tie to a parent. The bond is close, loud or both, and it shapes your drive.
The hard side is the same heat turned up too far. A family talk turns into a fight. A home turns into a place you defend rather than rest in. The work is to use the fire to build the base, not to burn it.
The neighbors differ. One house earlier, Mars in the third house turns the same drive toward daily talk and the near world. One house later, Mars in the 5th house puts it into play and romance. For the slow malefic in this same room, our page on Saturn in the 4th house tells a very different story. And since this room is linked to the sign of Cancer, read Mars in Cancer and the doctrine of fall too.
How to check your own chart
You need three things: your birth date, your birth place and your exact birth time. The time on a U.S. birth certificate is the local clock time, with daylight saving time if it was in force. Chart software converts clock time to sky time for you, so enter the clock time as written.
Then check three things. First, which house system your chart uses. If Mars sits near the edge of the 4th house, try both systems. Second, look for a small R next to Mars. That marks a retrograde Mars. Third, check where the Sun sits. If the Sun is in houses 7 to 12, you have a day chart. If it is in houses 1 to 6, you have a night chart.
A quick test works too. If you were born between 10 a.m. and 1 p.m. with Mars in the 4th house, your Mars is almost surely retrograde. If you were born between 5 p.m. and 6 a.m., it is almost surely direct.
How we measured this
We want these numbers to be checkable, so here is the method in full.
Places: the same 36 large U.S. metro areas as our other Mars house counts, from New York to San Jose, weighted by 2020 population. Each has its own time zone. Phoenix keeps standard time all year.
Dates: a regular grid of 8,885 dates, one every 3.7 days from 1940 to 2030. The step is not a whole number of days, so the grid does not keep landing on the same weekday. Within each date, one clock time every ten minutes. We applied today’s daylight saving rule to every date, so each hour means the same clock hour a U.S. parent would read.
Birth hours: either every hour equal, or each ten minute slot weighted by its share in the CDC natality file 2024, for all births and for each type of birth.
Sky positions: the Swiss Ephemeris, in its built-in Moshier mode. Retrograde means the daily motion of Mars along the zodiac is below zero. Houses: Placidus and whole sign, from our own house code. It matched the Swiss Ephemeris house routine within 0.01 degree on 3,000 test charts. Day or night: the Sun above or below the horizon at the same minute.
Check one: a second count on 150,000 random charts per case, drawn with a fixed seed. Each chart was cast by the Swiss Ephemeris house routine. With even hours, it gave 8.26 percent under Placidus, with 9.5 percent of those retrograde. With real hours, it gave 7.60 percent, with 12.4 percent retrograde. For C-section births, it gave 6.53 percent, with 19.3 percent retrograde. All sit within one or two margins of error of the main count.
Check two: a second library, astronomy-engine, placed Mars within 0.01 degree of the Swiss Ephemeris on 2,000 test dates.
Check three: a long window. We reran the grid on 12,541 dates from 1600 to 2400, one every 23.3 days. Under Placidus, it gave 8.25 percent with even hours and 7.55 percent with real hours. Mars was retrograde 9.3 percent of the time. The retrograde share among these charts was 12.5 percent with real hours and 18.5 percent for C-section births. The findings hold on the long run.
One limit is worth saying plainly. The CDC hours are from 2024. Births in 1950 were not timed by surgery plans the way they are now. For an older reader, the true figure sits between the even-hours row and the real-hours row.
Questions people ask
How common is Mars in the 4th house?
For U.S. births, about 7.5 percent under Placidus houses and 7.4 percent under whole sign houses, using real birth hours. That is about one chart in thirteen. With every hour equal, it would be 8.2 percent.
What birth time gives Mars in the 4th house?
Any time can, because the window moves through the day with the Mars cycle. On average, the most likely hour is 11 p.m. to midnight, at 13.5 percent. The least likely is 11 a.m. to noon, at 2.9 percent. Around opposition, the window moves to the late morning.
Is Mars in the 4th house above or below the horizon?
Below it. Mars there has set some hours before and is about to reach its lowest point, the IC. It gets there at the end of the house.
How many people with Mars in the 4th house have it retrograde?
About one in eight U.S. births, 12.6 percent under Placidus with real birth hours. The sky alone would give 9.4 percent. Among C-section babies, it is 18.7 percent, almost one in five.
Is Mars bad in the 4th house?
The old books call Mars a malefic, and the 4th house holds the parents and the home. So they read it as a hard guest on a strong angle. Ptolemy and Firmicus soften it for night births. With real U.S. birth hours, 64.4 percent of people with it are night births.
Why does my chart show Mars in the 3rd or 5th house instead?
Most likely your chart uses a different house system, or the birth time differs by a few minutes. Each window lasts about two hours, and Placidus and whole sign can disagree by an hour or more.
What to take from it
Mars in the 4th house is a midnight placement most years. It is more than four times likelier at 11 p.m. than at 11 a.m., because Mars spends most of its cycle near the Sun. The quiet night ward works against it, so on a U.S. hospital clock it falls to about one birth in thirteen.
For a few weeks every two years, it becomes a noon placement, and those are the weeks of the retrograde loop. That is why one Mars in the 4th house in eight is retrograde on the hospital clock, and almost one in five among C-section babies. Check your chart for the small R before you read any verdict about home and family.
Want the full picture of your own chart? An Astrovision report reads every placement for you, in writing and as a personal podcast. Discover your personal report.