What Are Planetary Hours, and Why Do They Change Length

You chose the day carefully. Thursday for the conversation about money, Friday for the message you had been sitting on for a week, because somewhere along the way you picked up that those days carry weight. The day came and nothing moved. The matter stayed exactly where it was before you started paying attention to any of this.

The day was probably right. The hour was almost certainly wrong.

Planetary hours are the layer underneath the days of the week, and in Western traditional astrology they are where the day is actually divided up. Most people who reach the days never reach the hours.

What are planetary hours

A planetary hour is one twelfth of daylight, or one twelfth of darkness, governed by one of the seven classical planets.

Sunrise to sunset is divided into twelve. Sunset to the following sunrise is divided into twelve. That gives twenty-four hours across the full day, and each one carries a planet, rotating in a fixed sequence.

The sequence runs Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon, then begins again. That is the order of the spheres as the old astronomers arranged them, working inward from the furthest body to the nearest, with the Moon closest to Earth. Once the sequence reaches the Moon it returns to Saturn and continues.

The first hour after sunrise belongs to the planet that rules the day. Sunrise on a Thursday opens the hour of Jupiter. Sunrise on a Friday opens the hour of Venus. Everything after that follows the sequence in order until sunrise the next morning.

The days of the week come out of this calculation

Start at sunrise on Saturday, in the hour of Saturn, and count twenty-four hours forward through the sequence. You land on the Sun, which opens Sunday. Count another twenty-four and you land on the Moon, which opens Monday. Keep going and you get Mars, Mercury, Jupiter, Venus, in that order.

That is the week, and it falls out of the arithmetic rather than out of anyone's preference.

The Romance languages kept the evidence in plain sight. Five of the seven survive intact in French: lundi for the Moon, mardi for Mars, mercredi for Mercury, jeudi for Jupiter, vendredi for Venus. English kept Saturday, Sunday and Monday, then swapped the other four for Germanic equivalents, which is why Tuesday and Thursday hide their origins while mardi and jeudi do not.

The hours came first, and the names of the days settled on top of them.

Why your hour changes length

Here is the part that catches people out. A planetary hour is rarely sixty minutes long.

Daylight gets divided into twelve regardless of how much daylight there is, so the length of an hour moves with the season. In Brisbane in late December, daylight runs close to fourteen hours. Split twelve ways, each daylight hour comes to roughly sixty-nine minutes. In late June the same city gets around ten and a half hours of light, so each daylight hour shrinks to about fifty-two.

The night hours do the opposite. Short summer nights make short night hours. Long winter nights stretch them out.

An hour of Venus in December therefore runs about seventeen minutes longer than an hour of Venus in June, and the two are the same hour by name only. This is also why the clock on your phone cannot tell you where you are in the sequence. Twelve noon means very little here. Sunrise is the anchor, and everything is measured from it.

The hours are different where you live

Sunrise and sunset shift with latitude and longitude, and the hours shift with them.

Brisbane, Melbourne and Perth are running different planetary hours at the same moment, and none of them match London. A printed table made for one city is simply wrong in another. The further you sit from the equator, the wider the seasonal swing becomes, which is why a Southern Hemisphere reader cannot borrow a table built for the North.

Your location and today's date are the only two things the calculation needs.

How to use the hour

The principle in traditional practice is straightforward. Match the action to the planet governing the hour, and you are working with the grain of the day rather than across it.

Jupiter governs money matters and anything you want to grow. Mercury takes contracts, messages and negotiation. Venus carries whatever depends on being received well, the date, the interview, the favour you have to ask for. The Sun holds authority and visibility. Saturn takes endings and boundaries, and anything you want closed cleanly.

These are the same seven planets that run through the whole of the older tradition, and what the seven planets each govern is worth knowing before you start matching actions to hours.

Tradition holds the window as strongest where the day and the hour agree. An hour of Jupiter on a Thursday is the most supported moment a week offers for a money matter.

Where you cannot wait for the day, the hour still works on its own. Jupiter hours occur on every day of the week, several times over, so you are rarely more than a day away from a usable window. That is the practical advantage of hours over waiting for rare alignments.

It also explains the Thursday that went nowhere. You can sit inside a Jupiter day and still make the ask in an hour of Saturn, which is the hour least inclined to hand anything over.

Where the hour stops

The hour is the finest grain of timing, and it is not the whole of it.

Astrology works in layers, and the hour sits at the bottom of a stack that runs from your Sun sign up to a single dated question. Above the hour sits the day. Above the day sits the Moon, which moves through its own cycle on a different schedule again, and what the New Moon and Full Moon are each actually good for answers a different question from the one this article answers.

For an ordinary decision, a message or a request or a purchase, the hour is enough on its own and it costs you nothing to use. For a beginning meant to last decades, a marriage or a company or a house, the hour is one factor among several, and choosing that moment properly is a longer piece of work.

Start with the hour. It is the layer you can act on today, and a fortnight of ordinary use will show you more than the reading will.

Find your hours

The hours run differently for every date and every location, so a table is only useful when it is built for where you actually are.

Check the current planetary hour for your location

The calculator gives all twenty-four hours for any date, with sunrise, solar noon and sunset, and the hour running right now marked live. Set it to your own city rather than the nearest capital, because even a few hundred kilometers moves the boundaries.