What are planetary hours?

Planetary hours are an ancient system that divides the time between sunrise and sunset into twelve 'hours', and the night into twelve more, each ruled by one of the seven classical planets — a way of giving every part of the day a character.

Are planetary hours 60 minutes long?

Not exactly. They stretch and shrink with the seasons. Daytime hours are longer in summer and shorter in winter, because the system splits actual daylight into twelve equal parts rather than clock-hours.

How do I calculate planetary hours?

You need the real sunrise and sunset times for your location and date. The day is split into twelve equal parts starting at sunrise; the first hour is ruled by the planet of that weekday, then the rest follow the classical Chaldean order.

Planetary Hours: The Oldest Way to Time Your Day

Planetary hours divide day and night into segments ruled by the seven classical planets. Here's what they are, where they come from, and how to use them.

Long before clocks, people told time by the sky — and gave each part of the day its own character. Planetary hours are one of the oldest of these systems, and they are still used in astrology and ritual today.

The idea in one sentence

Planetary hours divide the daylight into twelve parts and the night into twelve more, and hand each part to one of the seven classical planets — the Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn. Every hour, in other words, has a “ruler,” and that ruler colours the hour’s traditional character.

Why the hours aren’t 60 minutes

This is the part that surprises people. A planetary “hour” is not a clock hour. The system takes the actual time between sunrise and sunset and divides it into twelve equal pieces — so in summer, when days are long, the daytime hours are longer than sixty minutes, and in winter they’re shorter. The night’s twelve hours make up the difference.

That means planetary hours depend on where you are and the date — real sunrise and sunset at your location, not a fixed schedule.

The order of the planets

The first hour after sunrise is ruled by the planet of that day of the week — the Sun on Sunday, the Moon on Monday, and so on. From there the hours follow the Chaldean order, an old sequence based on how fast each planet appears to move: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon. When you reach the end, you start again.

It’s an elegant loop — and it’s the same logic that gives us the names of the days of the week in many languages.

What each ruler is traditionally “for”

People who work with planetary hours often pick an hour whose ruler suits the task at hand — as a ritual for focus, not a promise of results:

Sun — vitality, confidence, stepping into the light.
Moon — home, rest, tending to feelings.
Mercury — messages, learning, conversations.
Venus — love, connection, beauty.
Mars — drive, energy, courage.
Jupiter — growth, study, opportunity.
Saturn — discipline, planning, commitment.

None of this predicts an outcome. It’s a way of noticing the rhythm of your day and choosing a moment intentionally — a very old habit of paying attention.

Using them today

You don’t need a table of sunrise times and a pen. In MysticAlmanac, the day’s planetary hours are calculated from the real sunrise and sunset at your location, and mapped to the parts of your life — a good hour for a hard conversation, a good hour to rest — so the oldest timing system in the book takes about ten seconds to read.

Pick an hour. Notice what it’s for. That’s the whole practice.