Dates and Days

Moon sign calendar

Which sign the Moon is in, and what the tradition calls that day

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The month at a glance

Changeovers: every sign change this month, in UTC
DateTime (UTC)Moon entersDay type
How this was counted
Day type— Moon in— Element— Changes at— Next fruit day—

Moon positions are checked on every build against 105 JPL Horizons lunar positions. How it is checked

Pick a date to see which sign the Moon is in and whether the biodynamic tradition calls it a root, leaf, flower or fruit day. The day types are computed from the Moon’s sidereal position, so every changeover comes with the exact instant it happens.

What the four types are

The twelve signs carry the four classical elements, three signs each, and each element is associated with a part of a plant: the fire signs with fruit, the earth signs with root, the air signs with flower and the water signs with leaf. The Moon spends about two and a third days in each sign, so the four types come round roughly every nine or ten days.

The triplicities that give each sign its element are about two thousand years old, and the scheme is published identically by everyone who uses it. The recent and much more contested part is the twentieth-century proposal that the cycle governs how plants grow and, in the version that reached the wine trade, how a bottle shows on the day you open it.

The wine reading

Some drinkers and a number of tasting rooms use the same four types to decide when to open a bottle: fruit and flower days are held to be the days a wine shows best, and root and leaf days the days to leave it alone. It is a pleasant shared ritual that gives a table something to argue about and costs nothing to try.

There is no good evidence it is true. The underlying trials, run over decades, were about sowing, and they are contested. The one substantial independent study, over three years, found effects from other lunar rhythms but not from this one, and no controlled tasting result has been replicated either way. This page tells you what day the tradition says it is and makes no claim about what is in your glass.

Why this will not match your printed calendar

There are two reasons. This page divides the sky into twelve equal thirty-degree signs, while the published calendars use the observed constellations, which are very unequal: Virgo covers more than forty degrees of the ecliptic and Scorpius about seven. This page also computes its own sequence, because a printed calendar is somebody’s work and copying its day sequence would be taking it.

Naming the zodiac is what makes a sign checkable. This page uses the sidereal zodiac with the Fagan-Bradley ayanamsa, currently a little over twenty-five degrees from the tropical zodiac your horoscope uses. The method page gives the arithmetic.

Days that change type partway through

A sign lasts about two and a third days, so the Moon changes sign partway through about 44 percent of calendar days. A calendar that prints one type per day has chosen either the type at midnight or the one covering the most hours, without saying which. This page shows both types on a split day and lists every changeover instant in the table above, so you can see whether the bottle you are opening at eight in the evening is on the same side of the line as breakfast was.

Questions

Is this the zodiac my newspaper horoscope uses?
No. This uses the sidereal zodiac, which measures position against the stars, and newspaper horoscopes use the tropical zodiac, which measures against the equinox. The equinox itself moves, by about one degree every seventy-two years, so the two have drifted roughly twenty-five degrees apart, most of a whole sign. The gap is called the ayanamsa, and the value used here is the Fagan-Bradley one, twenty-four degrees two minutes and thirty-one seconds at 1950, carried forward by the standard precession formula.
Why does this not match the printed calendar I already own?
The two use different sign boundaries. This page uses twelve equal signs of thirty degrees each. The published biodynamic calendars use the observed constellations, which vary widely in size (Virgo spans more than forty degrees of the ecliptic, Scorpius about seven), so the day a type changes will often differ by a day or so, and occasionally more. Neither is wrong: they answer slightly different questions. This page also works out its own sequence, since a published calendar's sequence is its author's work.
Does the day type change how a wine tastes?
There is no good evidence that it does. The tradition's trials were about sowing seed, and even those results are contested. This page reports what the tradition calls the day, which is a fact about the tradition, and says nothing about the wine. Plenty of people find it a pleasant way to choose a bottle.
What happens when the Moon changes sign in the middle of the day?
The day gets two types, and both are shown with the time the changeover happens, in UTC. That is common: on average 44 percent of days hold a changeover, since the Moon stays only about two and a third days in each sign. The table under the grid lists every changeover in the month with its exact instant.
Where do root, leaf, flower and fruit days come from?
From the four classical elements, by way of the zodiac triplicities, which are roughly two thousand years old and appear in essentially every source on the subject. The fire signs Aries, Leo and Sagittarius carry fruit; the earth signs Taurus, Virgo and Capricorn carry root; the air signs Gemini, Libra and Aquarius carry flower; and the water signs Cancer, Scorpio and Pisces carry leaf. The idea that this cycle governs plant growth is a twentieth-century addition.