UTERSolunar tables work as astronomy but only weakly, if at all, as a bite predictor. The moon times they print are accurate. When scientists have tested whether fish actually bite more during the "major" and "minor" periods, the results range from a small effect for some species to no effect at all. The moon's most dependable influence on fishing comes through the tide.
That is not the answer most fishing apps lead with, so here is the evidence, what we think it means on the water, and exactly how much weight Fish Scouter gives the moon compared with the tide and water temperature.
Where solunar tables came from
John Alden Knight published his solunar theory in the 1920s. He collected fishing folklore and noticed that many of the "good times" matched the moon's position. His tables mark two kinds of window each day:
- Major periods: about two hours centred on the moon directly overhead (upper transit) and directly underfoot (lower transit).
- Minor periods: shorter windows around moonrise and moonset.
Because the moon rises about 50 minutes later each day, the windows slide later through the month. Around the new moon the moon is overhead near midday; around the full moon it is overhead near midnight. Many tables also rate days higher near new and full moons.
What the research says
Tests of the tables themselves: mostly no effect
The most direct test we know of is a 2023 paper in SN Applied Sciences by Quigley and colleagues. They compared more than five years of catch-per-hour records from regular river trout trips with the daily ratings and peak times of several popular solunar services. They found no significant relationship between catch rate and any of the solunar values, the lunar phase, or lunar illumination. Air temperature predicted catch rate better than any of the tables. The data came from one experienced angler on one kind of fishery, which is a real limitation, but it is a clean test. The paper also notes a much older Iowa study that found no link between catch and Knight's original peak times.
Big datasets: small lunar effects for some fish
Other studies do find patterns. Vinson and Angradi analysed angler records of roughly 342,000 muskellunge across North America (PLOS ONE, 2014). More muskies were caught around the full and new moon, but the effect was modest: an angler who fished only on the peak lunar day would catch about 5% more than one who fished random days. They also found angler effort followed the moon on at least one lake, so part of the pattern may be people, not fish.
A 2021 study of thirteen years of creel data from Escanaba Lake, Wisconsin, found that trips with the moon overhead or underfoot had slightly higher odds of catching a walleye or muskie. But the authors describe the effect on catch rate as small. For muskie, catch rates were actually highest on trips with neither lunar event.
In salt water, a study of nine years of offshore tournament catches in New South Wales, Australia (Lowry and colleagues, 2007) found species-specific patterns: some sharks, dolphinfish and yellowfin tuna peaked between the new moon and first quarter, while black marlin peaked between the full moon and last quarter. Several species showed no trend. The authors suggested prey moving with the lunar cycle as one explanation.
What we take from it
| Claim | Our read of the evidence |
|---|---|
| Moon phase changes the tide | Solid. New and full moons bring spring tides with bigger ranges and stronger current. |
| Some species feed on a lunar rhythm | Plausible and supported for some fish, but the effects found are small and differ by species. |
| Fish bite on a schedule set by the moon's position overhead or underfoot | Weak. Direct tests of solunar tables mostly find nothing; a few datasets show a small edge. |
| Solunar should outrank tide, temperature and light | Not supported by anything we have read. |
The moon's real job: tides and light
If you fish salt water, the moon already matters through the tide. Around new and full moons the tidal range is larger, so passes, bridges and creek mouths run harder. That is a big reason so many guides swear by "the moon tides" for tarpon in passes and snook on summer beaches. You do not need a solunar table to use that. You need a tide chart. Our guide to the best tide for fishing covers it structure by structure.
The moon also changes night light. A bright full moon lets predators hunt on shallow flats at night and can make the dawn bite slower. A dark new moon makes dock lights and bridge shadow lines stronger. Those are real effects on where fish are, but they are about light, not about a two-hour window on a calendar.
How Fish Scouter weighs the moon vs tide vs temperature
We include solunar periods because anglers ask for them and because some studies find a small effect. We just do not let them run the forecast. Here is how our saltwater bite score is built, starting from a base of 40 points:
| Factor | Points |
|---|---|
| Season (where the fish is that month, by region) | about +25 at peak down to −15 when it is not there |
| Water temperature from the nearest NOAA sensor | +25 ideal, +10 workable, up to −30 when too cold or hot |
| Moving tide (scaled by how much that species wants current) | up to +20 |
| Dawn or dusk (scaled by how much that species likes low light) | up to +15 |
| Recent catches logged nearby | up to +15 |
| Barometer falling / rising hard | +8 / −8 |
| Wind (light chop helps a little; 20 kts or more hurts) | +3 / −10 |
| Solunar major / minor | +6 / +3 |
So a solunar major can lift a species a few points, about the same as a light breeze. It can never make a cold-water, out-of-season fish look good, and it is always shown as a labelled reason ("Solunar major") so you can ignore it if you like. In fresh water, where there is no tide, the same +6 and +3 apply, alongside season, water temperature, pressure trend, wind, low light and river flow.
Our solunar times are the classic Knight-style calculation: the moon's age from a known new moon, the transit estimated from the phase and the sun's noon, majors an hour either side of overhead and underfoot, minors half an hour either side of rise and set. It is within roughly twenty minutes of an almanac, which is closer than any bite window needs.
How to use solunar times without being fooled by them
- Pick the day on wind and weather. A blown-out day is a blown-out day, whatever the moon is doing.
- Pick the hours on tide and light. Find the strongest moving water and see if it overlaps dawn or dusk.
- Use solunar as a tie-breaker. If two windows look equal and one has a major in it, fish that one.
- Keep your own log. If you record your catches, you will learn more about your water in a season than any table can tell you.
See it for your spot
We built Fish Scouter as the honest alternative to a moon calendar, and we think it's the best way to know what's biting. It puts the moon phase, the major and minor periods, the tide and the prime windows side by side. It gives the moon only the weight the evidence supports, and every species score lists its reasons, so you can see exactly what the moon is and is not adding. Try it free.