Data sources & attribution

NOAA CO-OPS tide, water level and current data

Source: NOAA National Ocean Service, Center for Operational Oceanographic Products and Services, tidesandcurrents.noaa.gov, via the CO-OPS Data API and Metadata API.

• Live in your browser: 15-minute and high/low tide predictions (datum MLLW, feet, local time), latest observed water level (preliminary, unverified), and current predictions (slack, max flood, max ebb).
• Refreshed weekly at build time: station list and coordinates, tidal datums, NOAA flood thresholds, and 12 months of high/low predictions used for the king-tide and minus-tide lists, plus a three-week offline copy.

License: works of the U.S. Federal Government are not subject to copyright in the United States (17 U.S.C. §105) and NOAA data is provided for public use. NOAA does not endorse this site. NOAA notes that observed data shown in real time is preliminary and that predictions are not a substitute for official navigation products.

Sun and moon

Calculated by this site’s own code from published astronomical formulas (J. Meeus, Astronomical Algorithms, 2nd ed.). No third-party data is used. Checked against U.S. Naval Observatory values in our test suite.

Time zones

Station times use the station’s local standard/daylight time as published by NOAA, and the IANA time-zone database built into your browser.