About TidesMap

TidesMap shows tide times for US coastal stations in a form you can read in a second: a dial that shows where the water is between low and high, the next tide in big type, and a chart you can drag through the day.

Where the numbers come from

All high and low tide times and heights are tide predictions from NOAA CO-OPS, downloaded from the NOAA CO-OPS data API. Heights are in feet above Mean Lower Low Water (MLLW), the datum used on US charts. Times are shown in each station’s local time, including daylight saving time.

• Reference stations have their own harmonic predictions from NOAA.
• Subordinate stations get their highs and lows from a nearby reference station, with time and height corrections published by NOAA.
• The smooth curve between highs and lows is drawn by TidesMap with a cosine curve, so heights between the turning points are an estimate. The high and low times and heights themselves are NOAA’s.
• Sunrise, sunset and the moon phase are calculated in your browser from the station’s position.

How fresh is it?

Each station carries NOAA predictions for the next 13 months, and the page works out “today” in your browser, so it never shows yesterday’s tides. The data is rebuilt from NOAA every month. This build: 2026-11-02.

Not for navigation

Predictions are astronomical. Wind, storms, river flow and air pressure can make the real water level differ a lot. Do not use TidesMap for navigation or safety decisions; check official NOAA products, local warnings and real-time water levels. The “Good for” tips are rules of thumb only.

Privacy

No account and no cookies. Favourites and recently viewed stations are stored only in your browser (local storage). “Near me” asks your browser for your location and uses it only on the page to find the closest stations. The map loads tiles from OpenFreeMap. Visits are counted with Cloudflare Web Analytics, which does not use cookies or track you across sites.

Credits

Tide predictions: NOAA CO-OPS (US government data). Map: OpenFreeMap, © OpenMapTiles, data © OpenStreetMap contributors, rendered with MapLibre GL JS. TidesMap is not affiliated with or endorsed by NOAA.