How It Works

Tide Data from NOAA

Tidesy gets its tide predictions from NOAA, the National Oceanic and Atmospheric Administration. NOAA operates approximately 3,000 permanent tide stations around the U.S. coastline, each one recording water levels for decades. Using that historical data, NOAA builds mathematical models called harmonic analyses that predict exactly when the water will rise and fall at each location.

Every six minutes, Tidesy fetches a fresh set of 240 predictions covering the full 24-hour day. Each prediction is a tide height at a six-minute interval, measured in feet above or below a reference point called MLLW (Mean Lower Low Water). MLLW is the average of the lowest daily tides over a 19-year period. A positive number means the water is above that average low mark. A negative number means it is unusually low. This is the same data that mariners and coastal planners rely on.

Weather Alerts from the National Weather Service

Tidesy checks for active weather alerts at your location every six minutes using the National Weather Service API. Alerts are color-coded by four severity levels: Minor (gray), Moderate (yellow), Severe (orange), and Extreme (red). The types most relevant to coastal users include Coastal Flood Advisories, High Surf Warnings, Rip Current Statements, Small Craft Advisories, Tsunami Watches, and Beach Hazards Statements.

When alerts are active, a banner appears on the device display and detailed cards show up on the web dashboard. Each alert includes what is happening, where it affects, when it starts and ends, and what impacts to expect. You get the same official government alerts that emergency managers use, delivered to your countertop.

Current Weather from MET Norway

Temperature, wind speed, and wind direction come from MET Norway's open weather API. This data appears on both the device display and the web dashboard alongside the tide information, so you get the full picture of conditions at each station without switching to a weather app.

How the Data Flows