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Free tool · Planetary hours

Planetary Hours Today: for your location.

The 24 planetary hours for today where you are: sunrise, sunset, the ruling planet of each hour in the classical Chaldean order, and what the current hour is traditionally used for.

Sunrise and sunset for the place set the hours. Pick a place from the suggestions.

Planetary hours divide daylight into twelve equal parts and darkness into twelve more, so an hour is longer than sixty minutes in summer daytime and shorter in winter. Each hour is assigned a planet in the Chaldean order, Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon, beginning at sunrise with the ruler of the day.

The system is older than the seven-day week's names, which come from it. Electional astrology uses the hours to choose moments for beginnings; the tool shows the schedule and the traditional associations of the current hour.

How it is computed

Sunrise and sunset are computed for the place's coordinates and today's date. The planetary day begins at sunrise, not midnight, so between midnight and dawn you are still in the previous day's night hours. Rulers follow the Chaldean order from the day ruler: Sun on Sunday, Moon on Monday, Mars on Tuesday, Mercury on Wednesday, Jupiter on Thursday, Venus on Friday, Saturn on Saturday.

Common questions

Why is a planetary hour not sixty minutes?
Because daylight is divided into twelve equal parts whatever its length. In June at high latitudes a day hour can run 80 minutes and a night hour 40; at the equinox they are close to 60.
What are planetary hours used for?
Traditionally for choosing a moment: a Mercury hour for a letter, a Venus hour for a meeting about affection, a Saturn hour for a boundary. Chapter 32 of the course covers electional basics and their limits.
Does my time zone matter?
Only for display. The hours are set by the Sun at your coordinates; the tool shows them in the place's local time.

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Positions are computed from the JPL DE442 ephemeris in the Tropical zodiac with Placidus houses. Readings are educational, drafted from the computed factors and edited by the Shymea team; they are not the work of a named practising astrologer and are not medical, legal or financial advice. See the editorial policy.