Solunar bite times, and the formula behind them
CatchClock publishes solunar bite windows for US cities: a two-hour major period around each crossing of the Moon over your meridian, and a one-hour minor period around moonrise and moonset. Every time is computed from the city's own coordinates when the site is built — including the 6.8% of days that carry one major period instead of two.
Where to start
If you want times for a specific place, the fishing forecast by city grid is the way in: each city page carries its own sun and moon times, major and minor periods, and the waters and species that actually matter there. If you want to understand what those windows are before you trust them, read best fishing times, then the solunar fishing calendar, which walks through a month of windows and what changes across a lunar cycle.
Timing is only half of a fishing day. How to catch fish collects the technique side and links out to species guides — bass, catfish and trout among them. In Florida we also publish a Florida fish identification key for working out what you just landed, and a guide to Florida fishing spots for where to put in. If you would rather have all of this on a phone, our comparison of fishing apps lays out what each one does well, ours included, and where each one loses.
How the windows are calculated
A major period is two hours wide, centered on the Moon's meridian transit — the moment the Moon crosses your line of longitude, overhead or underfoot. A minor period is one hour wide, centered on moonrise and on moonset. That convention comes from John Alden Knight, who published the first solunar tables in 1926, and it has not changed since.
What differs between publishers is whether the transit is computed properly. We solve for hour angle 0 and 12 rather than looking for the Moon's peak altitude, because those two moments are not the same: across 760 culminations they drifted apart by as much as 8.6 minutes, which is 7% of a major window. The full method, the references we check against and the numbers behind that measurement are on how we calculate bite times.
What we do not claim
Solunar theory is a prediction, not a measurement, and it has no rigorous scientific confirmation. A front, a pressure drop or a swing in water temperature will beat any lunar window, and none of the three is in this model. On tidal salt water the tide matters more than the Moon, and our tables do not replace a NOAA station's predictions. Seasons, size limits and bag limits we do not restate at all: every city page links the state agency instead, because that is the only source that is right on the day you read it. More about the project, and about what we deliberately leave out, is on the about page.
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Written and checked by CatchClock Editorial, the editorial and data team behind these calculations.