Full moon calendar

The names on this full moon calendar — Wolf, Snow, Worm, Pink, Flower, Strawberry, Buck, Sturgeon, Corn, Harvest, Hunter's, Beaver, Cold — come mostly from North American colonial and Algonquian usage, collected and popularised in twentieth-century almanacs. They describe what was happening on the ground in that month rather than anything about the Moon.

Two of them are not month names at all, and this is where most published tables go wrong. The Harvest Moon is the full moon falling nearest the September equinox, and the Hunter's Moon is the one after it. In most years that puts Harvest in September — but not all years, and a table that assigns it by month will be wrong in the others.

The Harvest Moon earned its name from a real effect rather than a poetic one. Around the September equinox the Moon's orbit meets the horizon at a shallow angle, so successive moonrises come only 20 to 30 minutes later each night instead of the usual 50. The result is several evenings of bright moonlight arriving right after sunset — genuinely useful if you are bringing in a crop by hand.

The names are also not universal, and it is worth saying so. These are one regional tradition among many; Chinese, Hindu, Māori and countless other calendars name their lunar months differently and start them at different points in the cycle. What this full moon calendar publishes is the set that English-language almanacs standardised on, because that is the set a reader comparing pages will be comparing against.

Every entry in this full moon calendar carries the sign and degree the Moon occupies at that instant. Because a full moon is by definition opposite the Sun, the Moon's sign is always the sign opposite the Sun's — a full moon while the Sun is in Leo is a full moon in Aquarius, every time.

That makes the sign predictable to anyone who knows the date, and it is exactly why the degree is the interesting number rather than the sign. A full moon at 2° of a sign and one at 28° are nearly a month apart in the cycle they belong to, and only one of them will be within orb of anything in a given birth chart.

In astrological practice the full moon is read as a culmination rather than a beginning: something reaching the point where it has to be dealt with. Which part of your life that touches depends on which house of your own chart the degree falls in, and a date alone cannot tell you that.

Because the full moon is always opposite the Sun, the sequence of signs across a year is fixed and marches forward one place a month. What is not fixed is the degree, and in a thirteen-full-moon year it runs backwards — which is the pattern the diagram above makes visible and the reason two consecutive Januarys can put the full moon at very different points in the same sign.