Solunar Calendar

In October, 14 of 31 days rate good in San Diego. The new moon of October 10 counts for October 9 to 11 and the full moon of October 25 counts for October 24 to 26. Sunrise or sunset falls inside a major period on October 2 to 3, October 16 to 19 and October 30 to 31, around the last quarter on October 3, the first quarter on October 18 and the last quarter on November 1. No day has both, because near new and full moon the moon passes its highest and lowest points close to midday and midnight, far from sunrise and sunset.

The calendar is for San Diego; change the place at the top of the page.

Solunar tables go back to the angler and author John Alden Knight. As the FWC tells it, Knight started in 1926 from fishing lore he had picked up in Florida, weighed 33 things that might explain why fish feed at some hours and not others, and kept three: sunrise and sunset, the moon's phase and the tide. He came to believe that the positions of the sun and moon counted for more than the state of the tide, and named the theory "solunar", from sol for the sun and lunar for the moon.

Knight published his first tables in 1936, the year Scribner's brought out his book The Modern Angler, Including the Solunar Theory, and followed it in 1942 with Moon Up, Moon Down.

Knight split each day into major and minor periods. Major periods center on the moon's two transits: the moment it stands highest in the sky (the upper transit, "moon overhead") and the moment it is lowest, on the far side of the Earth (the lower transit, "moon underfoot"), roughly half a day later. Minor periods center on moonrise and moonset.

On this site a major period runs from 1 hour before a transit to 1 hour after it, and a minor period from 30 minutes before moonrise or moonset to 30 minutes after. Not every table uses these lengths. The FWC describes periods of 1.5 to 3 hours, depending on where the moon stands in relation to the sun, so other tables can start and end their periods at different times than ours.

We compute the moon's position for each place's coordinates with the SunCalc library. A transit is the moment the moon's height in the sky peaks or bottoms out; moonrise and moonset are the moments the top edge of the moon meets the horizon, the same convention the US Naval Observatory uses. Each period is listed under the date of its transit, rise or set. Because the moon keeps coming up later (the week summary above gives the figure for the days shown), now and then a date has no moonrise, no moonset or only one transit, and the tables show a dash.

The phase decides where in the day the periods fall. According to the US Naval Observatory, a new moon crosses the meridian at about the same time as the sun, a first quarter moon about 6 hours after it, a full moon about 12 hours from it, and a last quarter moon about 6 hours ahead of it. Near new and full moon, then, the major periods sit near midday and midnight and the minor periods near sunrise and sunset. Around the quarter moons it is the other way round: the major periods move to the start and end of the day.

That is why the two factors in our day rating rarely, if ever, meet. The FWC rates new and full moon days highest, and the magazine article cited below favors solunar periods that fall close to sunrise or sunset. In our California data the first happens around new and full moon and the major periods reach sunrise and sunset only around the quarter moons.

Solunar tables are a traditional method, not a guarantee. Knight built the theory from anglers' lore and his own observations, and even a fishing magazine that explains the method points out that it has never been proven scientifically. The FWC warns that weather can count for more than the tables, naming a falling barometer in particular. Nothing on this page says that fish bite more during a major period; use the periods as one way of choosing a time, if you like the method, and look at the tide and the conditions before you go.