☉ Planetary Hours Calculator — Today's Hours for Your Location
Umbriel calculates today's planetary hours for wherever you are, free. Long before clocks, the day was divided into twelve daylight hours and twelve night hours, each ruled by a planet in a fixed rotation.
- What you'll needYour location (for local sunrise and sunset)
- What you getEvery planetary hour for today, day and night, with the current hour marked
- CostFree — no account required
Runs in your browser. Nothing to install, nothing to set up.
What planetary hours actually are
Planetary hours are older than the equal hour. Take the time from sunrise to sunset and divide it into twelve — those are the daylight hours, and in summer each is considerably longer than sixty minutes. Do the same from sunset to sunrise for the night hours. Because the calculation is tied to actual sunrise and sunset, planetary hours are genuinely local.
The rulers rotate in the Chaldean order — Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon — repeating endlessly. The first hour after sunrise is ruled by the planet that governs the day itself, which is where our weekday names come from: Sunday's first hour is the Sun's, Monday's the Moon's, Saturday's Saturn's.
Traditional practice used them for timing: a Venus hour for reconciliation or anything to do with beauty, a Mercury hour for correspondence and negotiation, a Jupiter hour for asking a favour, a Saturn hour for finishing things. Whether or not you hold with the symbolism, dividing a day by light rather than by clock is a quietly different way to experience it.
What's in your result
- Day hoursSunrise to sunset in twelve parts — longer than sixty minutes in summer, shorter in winter.
- Night hoursSunset to sunrise, likewise in twelve.
- The Chaldean orderSaturn, Jupiter, Mars, Sun, Venus, Mercury, Moon — the rotation the whole system runs on.
- The day rulerThe planet of the first hour after sunrise, which names the day of the week.
- What each hour suitsTraditional associations — Venus for reconciling, Mercury for messages, Jupiter for asking, Mars for effort, Saturn for endings.
Common questions
What are planetary hours?
A pre-clock way of dividing the day: twelve unequal hours from sunrise to sunset, twelve more from sunset to sunrise, each ruled by one of the seven classical planets in a fixed rotation.
Why aren't planetary hours sixty minutes long?
Because they divide actual daylight into twelve, and daylight varies with the season and your latitude. A summer daylight hour can run well over sixty minutes while the night hours run short.
How do I find the current planetary hour?
Umbriel calculates the full day for your location from local sunrise and sunset and marks the hour you're in right now.
Where do the days of the week come from?
From this system. Each day is named for the planet ruling its first hour after sunrise — Sunday the Sun, Monday the Moon, Saturday Saturn, with the others surviving through Norse and Romance equivalents.
Go deeper
Every one of these is a page in its own right, written out one at a time.
Related free tools
Umbriel offers every system here as a set of prompts to think with, never as a statement of fact about who you are. Take what's useful, leave the rest.