Moving Water
Tide, solunar, and bite timing for US inshore fishing.
Need help, found a bug, or think a species is scored wrong? Email me — I read everything, and feedback from people actually on the water is what makes the numbers better.
lukesalm@icloud.comCommon questions
Where does the tide data come from?
NOAA CO-OPS — the U.S. National Oceanic and Atmospheric Administration's public tide service, covering 3,499 stations across every US coast, Alaska, Hawaii, and the territories. It's free and requires no key. The app needs a network connection to fetch predictions; everything else works offline.
Why does the app need a week's notice to be accurate?
It doesn't. Tide predictions are computed from harmonic constituents rather than forecast from observations, and sun and moon positions are deterministic. Next Saturday's tide is exactly as accurate as this afternoon's. That's why "Plan the week" is trustworthy — and why weather, which genuinely is uncertain, is deliberately not in the model yet.
What does the bite score actually mean?
It answers "how good is this window for this species, at this spot, relative to that species' own best" — not "how likely am I to land one." That's why difficulty is shown separately as a tag (Forgiving through Low-percentage). A prime tarpon window is still a low-percentage day, and the app says so rather than hiding it in the number.
Seasonality is built into the score, because that's a question of whether the fish is physically present.
Are the species numbers scientific?
No, and the app is honest about that. The tide preferences, current dependence, and difficulty ratings are informed heuristics from general angling knowledge, not measured data. They're a starting point. Your catch log records the conditions at every fish you land, which is the ground truth those numbers will eventually be tuned against.
Does the timer keep running if I close the app?
Yes. A session stores when it started and works out elapsed time when you come back. You can close the app, lose signal, or restart your phone and the time will still be right — with no background activity and no battery cost.
Where are my photos stored?
On your device only. There's no server and no account. See the privacy policy.
I dropped a pin and can't find it again.
Tap See my pin on the map under your spot name on the home screen. The map opens centred on your pin, and the My pin button snaps back to it if you pan away.
Why is the nearest station not the city I searched for?
That's intentional. The gauge closest to where you actually fish is often not the city's headline station — a pin near Fort De Soto snaps to Tierra Verde, a fifth of a mile away, rather than downtown St. Petersburg. Tapping the map is the most accurate way to pick a spot.
Requirements
- iPhone or iPad running iOS 17 or later
- A network connection to fetch tide predictions
- Location, camera, and photo access are all optional