Fish Forecasts: What They Are, What They Can and Cannot Tell You
Quick Answer
A fish forecast is a prediction of how likely fish are to feed at a given place and time, built from measurable water and weather conditions rather than folklore. FishRadar publishes one for 851 named fishing spots and can score any coordinate on demand: a 0–100 number derived from water temperature and its departure from the seasonal normal, wind and wave state, barometric pressure trend, current, tide phase where tides matter, chlorophyll (a proxy for how productive the water is), depth from bathymetry, and solunar timing. What a fish forecast cannot do is tell you that you will catch fish. It tells you whether the water is behaving the way it behaves on good days at that spot — which is genuinely useful, and is not the same claim.
What goes into the score
Nine families of signal, all measured rather than assumed:
Water temperature, and its anomaly. The absolute number matters, but the departure from that location's own seasonal normal matters more. Water running 2 °C warm pushes cool-water species deeper or further offshore and brings warm-water species in ahead of the calendar.
Thermal structure. Mixed-layer depth tells you how far down the surface temperature is a useful guide. A shallow mixed layer means surface readings describe where fish are holding; a deep one means the whole column is similar.
Wind and waves, including the split between wind sea and primary swell. Moderate wind usually helps by breaking up surface light and moving bait; a big short-period wind sea usually does not.
Barometric pressure and its trend. The direction over the previous several hours carries more information than the reading itself.
Current speed and shear. In saltwater, moving water concentrates bait. The difference between surface and deeper current is often what stacks it.
Tide phase, where tidal range is large enough to matter — which is the important caveat below.
Chlorophyll and fronts. Chlorophyll indicates productivity; a sharp gradient (a front) is a line worth working along rather than across.
Depth and seabed shape, from GEBCO bathymetry.
Solunar timing — sun and moon position, which set the major and minor feeding windows.
Every one of those is a number from a live model or satellite source, refreshed daily. The weighting differs by water type: a freshwater lake score leans on temperature, depth and structure, while a saltwater score adds tide, current, salinity and chlorophyll.
Reading a score honestly
A score is a comparison, not a promise. 78 does not mean "78% chance of a fish". It means the conditions at that point resemble the conditions that score highly there. Two useful habits: compare a spot against itself over days rather than against a different spot, and treat a 3-point difference as noise.
Scores cluster high, and you should know why. Across the 659 spots scored on 29 July 2026 the global mean was 63.8, and most days most spots land between roughly 55 and 86. That is partly real — the spots in the catalogue are places people fish, not random ocean — and partly a property of any index built from continuous variables. The practical consequence: a 90 is meaningfully better than a 70, but a 66 versus a 63 tells you almost nothing.
Tidal range decides whether tide belongs in the answer at all. On the Atlantic coast of North America, tide is often the strongest single timing signal. In the Mediterranean and the Black Sea the tidal range is roughly 20–30 cm, and a forecast built around tide there is answering a question the water is not asking. FishRadar leads Mediterranean and Black Sea pages with sea-surface temperature trend, wind, wave, pressure and solunar timing instead, and says so on the page.
Data can be missing or stale, and the page will tell you. When a spot's data is more than 48 hours old, the live conditions block is withheld rather than presented as current. A confident number over stale inputs is worse than no number.
What a fish forecast will not do
It does not know about the fish. No forecast sees stocking schedules, a commercial net set the night before, a local algal bloom, or the fact that the water you are looking at was churned by forty boats on Saturday.
It does not replace local knowledge. Which bank, which depth, which lure — that is knowledge held by people who fish a water repeatedly. A forecast tells you when to go and roughly what the water is doing; a local tells you where to stand.
It is not a substitute for the regulations. Season, size and bag limits are law and vary by jurisdiction, sometimes by water. FishRadar publishes structured regulations for the jurisdictions it has verified, with the source cited, and states plainly where coverage is partial.
It cannot be validated by a single trip. One blank day on a 90 proves nothing, and one good day on a 40 proves nothing either. Judge a forecast the way you would judge a weather forecast: over dozens of outings, not one.
How to use it in practice
Pick the day, not the spot, first. Look at the same water across the next week and choose the day whose conditions are best for it.
Then pick the window. Solunar peaks and, on tidal coasts, the mid-tide flow windows are usually where the day's best hours sit.
Check what is driving the score. A high score built on a falling barometer behaves differently from one built on a warm-water anomaly.
Check the rules before you keep anything. Sizes and seasons change; the page states when its regulation data was last verified.
Keep your own record. After ten or fifteen trips you will know how the score maps onto your water and your species, which is worth more than any general rule.