How we calculate

Every date on Retrograde Daily is calculated from real planet positions, not copied from a list or guessed.

Where the numbers come from

We use a professional astronomy library that calculates where each planet appears in the sky at any moment. Its results are checked against data from NASA’s Jet Propulsion Laboratory, the same data astronomers use. It works for any date from 1900 to 2100.

How we find a retrograde

A planet turns retrograde at the moment its movement across the sky stops and reverses. We check each planet’s position over time, find the exact moment it changes direction, and narrow it down to the minute. The shadow periods come from the positions where the planet stops.

Which zodiac we use

We use the Western (tropical) zodiac, which is the one most horoscopes in Europe, North America and Australia use. It starts at the spring equinox. (Vedic astrology uses a different, sidereal zodiac, so its sign dates are different.)

How we check ourselves

• Every retrograde date from 2024 to 2030 is compared automatically against NASA JPL data and two published calendars.
• If any date disagrees, the site doesn’t update until it’s fixed.
• We test tricky cases too, like retrogrades that start near midnight or around clock changes.

Your time zone

We store every moment in universal time and show it in your device’s time zone, so “tonight” means your tonight.

How “your” reading is chosen

We count from your sun sign to the sign the planet is in. That number, 1 to 12, is the life area the retrograde touches for you. It’s the classic “solar house” method used in sun-sign astrology.

Spotted something that looks wrong? Tell us with the feedback box and we’ll check it.

How it's measured

We add up every planet that's retrograde today. The fast, personal planets (Mercury, Venus, Mars) count most, Jupiter and Saturn less, and the slow outer planets only a little. A planet counts most in the days it stands still and turns, a bit less in the middle, and a little in its shadow weeks. On your sign page, a planet in your own sign counts a little more.

It shows how busy the sky is, not what will happen to you.