Solunar Calendar Calculator - Major and Minor Feeding Times by Date

Anglers and hunters have long used solunar tables to pick the best hours of the day. This calculator estimates the major and minor solunar periods for any date, plus the moon phase and illumination, from date math alone. It is free, needs no account, and works for planning trips days or weeks ahead.

What solunar theory claims

Solunar theory, made popular by John Alden Knight in the 1930s, says that fish and game are more active at certain times tied to the Moon. The major periods happen when the Moon is directly overhead or directly underfoot, and they last about two hours each. The minor periods happen roughly halfway between the majors and last about one hour each. Many anglers report better catches during major periods, especially when a major period lines up with dawn or dusk. Scientists have not proven the effect, and weather, season and local conditions matter at least as much. Treat solunar times as one planning factor among several, not as a guarantee, and you will use them wisely.

How this calculator estimates the periods

The Moon returns to the same place in the sky every 24 hours and 50 minutes, which is the lunar day. The calculator anchors its math on a known new moon, 6 January 2000, and steps forward in lunar days to your chosen date, adjusting for your longitude, because the Moon crosses overhead at different clock times in different places. Major periods are centred on the overhead and underfoot transits, with one hour on either side. Minor periods are centred about six hours and twelve minutes from the majors, with half an hour on either side. The moon’s age, phase name and illumination come from the same date math: age in days since the new moon, divided by the 29.53-day lunar cycle. No live data is used, so the tool works for past and future dates alike.

How to use the calculator

Enter the date of your trip and your longitude. You can find your longitude in any map app; for London it is about -0.12, for New York about -74. Press the button and read the phase line first: it gives the moon phase, its age in days, and how much of its face is lit. Then read the table, which lists each period with its start, peak and end times, in UTC and in your browser’s local time. Plan your outing so that the peak of a major period falls inside your time on the water or in the field. If a major period lines up with sunrise or sunset, many solunar followers count that as the best combination of all.

Combining solunar times with real conditions

Solunar periods do not override weather. A cold front, a sudden wind change, or a sharp drop in water temperature can shut down feeding whatever the Moon is doing. Season matters too: fish follow spawning seasons and food availability, and game follows rutting and feeding patterns that shift through the year. Use the calculator to choose between two otherwise equal days, or to decide whether to start at dawn or to wait for the afternoon major period. Keep a simple log of your trips with the solunar periods, the weather and the result. After a season, your own log is worth more than any table, because it reflects your waters and your quarry.

A worked example

Suppose you plan a fishing trip on 27 October 2026 near London. The calculator shows a major period peaking in the early hours, a minor period in the morning, an underfoot major period in the early afternoon, and another minor period in the evening. If you can only fish one session, the afternoon major period is the natural pick, and you would plan to be on the water an hour before its peak and stay an hour after. If you can fish at dawn as well, you add the morning minor period as a bonus. This kind of planning is the whole point of the tool: it turns a vague idea about the Moon into concrete hours you can put in your diary.

Limits and honesty about accuracy

These are estimates. The simple lunar-day model ignores the Moon’s elliptical orbit, the tilt of its path, and the equation of time, so real transit times can differ by tens of minutes from the calculator’s figures. Published solunar tables differ from each other for the same reason: every table uses its own approximation. Use the periods as windows, not as exact minutes, and arrive early. The tool is for recreation planning only. It is not a substitute for local knowledge, safety checks, or fishing and hunting rules, which you must always follow.

Solunar Calendar Calculator – Major and Minor Feeding Times by Date