What are planetary hours?

Planetary hours are an old way of dividing time. Daylight, from sunrise to sunset, is split into twelve equal hours and the night into twelve more, and each hour is ruled by one of the seven classical planets in a fixed order. The first hour of each day belongs to that day’s own planet, which is why Sunday starts with the Sun, Monday with the Moon and Saturday with Saturn.

The order of the planets

The hours follow the old order of the planets from slowest to fastest, as seen from the earth: Saturn, Jupiter, Mars, the Sun, Venus, Mercury and the Moon, then round again.

Why the hours change length

Because they divide the real daylight, a summer day-hour is longer than a winter one, and the night-hours shorter. That is why planetary hours have to be worked out for your own town and date, from its sunrise and sunset.

How the days got their names

Run the order through all 24 hours of a day and the next day begins with a different planet: the Sun’s day is followed by the Moon’s, then Mars’s, Mercury’s, Jupiter’s, Venus’s and Saturn’s. That is the order of the week: Sunday, Monday, Tuesday (Mars’s day, dies Martis in Latin), Wednesday (Mercury’s, mercredi in French), Thursday (Jupiter’s, jeudi), Friday (Venus’s, vendredi) and Saturday (Saturn’s).

What each planet’s hour was for

In Lead to Gold

Lead to Gold works out the planetary hours for the town you pick, on your phone; it never asks for your location. Which planet rules your birthday?

Last updated October 24, 2026.

Lead to Gold: Shadow Work, on Google Play

The alchemists’ Great Work, made into ten quiet minutes a day: twelve gates, a private journal, and a line of wisdom from the old masters. Free to download, for Android.

Get it on Google Play

Keep reading