The astronomy
- Engine: all lunar and solar positions, the Moon's ecliptic longitude, phase angle, illuminated fraction, moonrise/moonset, sunrise/sunset, equinoxes and solstices, are computed in your browser with Astronomy Engine by Don Cross (MIT license), an implementation based on the VSOP87 planetary theory, accurate to about one arcminute over the years 1700–2100.
- Moon sign: the sign shown is the tropical zodiac sign containing the Moon's geocentric ecliptic longitude, the convention traditional American almanacs use. It is an almanac convention, not a claim about constellations.
- One reading per day: each calendar day's reading is evaluated once, at local noon in your timezone, so the score, phase name, and illumination you see are the same everywhere on the site all day.
- Phase names: derived from illumination and direction. "First Quarter" and "Last Quarter" are only used when the Moon is 45–55% lit; below that it's a crescent, above it a gibbous; within 2% of new or full it's the New or Full Moon.
The weather
Current conditions come from OpenWeatherMap; city-name suggestions from Open-Meteo geocoding. Weather is shown as a practical note and is never part of the Sign Index.
The Sign Index
The daily Sign Index starts at a neutral 50, then adds three lunar terms: the Moon's sign (fruitful +20 · semi-fruitful +7 · barren −15), the phase direction (waxing +6 · waning −6), and a small illumination adjustment (±5). The result is clamped to 2 to 98; in practice the daily overall index falls between 24 and 81, and activity scores can range wider. The score maps to six bands from Excellent to Avoid; all six band names and their thresholds are listed in How the Sign Index Works. The full breakdown, with each day's actual numbers, is on the Sign Index page.
Activity scores (planting, fishing, haircuts, and so on) are a separate traditional layer scored per activity from the same lunar facts.
The folklore
The correspondences we use are the common ones of the American and European almanac tradition:
- Fruitful / barren signs: water signs (Cancer, Scorpio, Pisces) most fruitful; Taurus, Capricorn, and Libra workable; the rest barren. Found throughout planting-by-the-signs lore as carried by historic farmers' almanacs.
- The body map (Man of Signs): the medieval homo signorum, running Aries at the head to Pisces at the feet. History in The Woman & Man of Signs.
- Waxing/waning timing: start and grow under a waxing Moon, finish and clear under a waning one, the oldest and most widespread almanac rule of thumb.
We present these as cultural tradition. They are not scientific claims, and the site never mixes them into the astronomical facts without labeling.
Licenses & credits
- Astronomy Engine: © Don Cross, MIT license.
- Weather data: OpenWeatherMap, used under their free-tier terms with attribution.
- Geocoding suggestions: Open-Meteo, CC-BY 4.0.