How to read a tide table without treating the prediction as a promise

Start with the station, not the height

A tide prediction belongs to a particular station. NOAA says accurate predictions depend on locations where tide data have been collected and analysed, and its U.S. Tide Predictions service covers more than 3,000 locations.

That makes the station name the first check. A table from a nearby harbour is not automatically a precise description of another beach, inlet or river mouth. If you are outside the United States, use the equivalent national or local hydrographic authority and read its station notes rather than transferring NOAA-specific datums or station rules.

Read the frame around every number

In NOAA Tide Predictions, the interface lets you choose feet or metres, a time zone, a clock format and, for harmonic stations, a reference datum. Those settings change how the same prediction is displayed, so a height without its unit and datum is incomplete.

Station type matters too. NOAA generates harmonic-station predictions from tidal harmonic constants. At subordinate stations, it starts with high and low predictions at a designated reference station and applies time and height adjustments; subordinate-station heights are presented relative to Mean Lower Low Water in NOAA’s system.

• Confirm the station name or station ID
• Check whether times are local daylight time, local standard time or GMT
• Read the height unit before comparing values
• Keep the stated datum attached to every height

Treat the table as a tide prediction, not a live observation

NOAA provides tide predictions and real-time water-level observations as different products. That distinction matters because tide tables estimate the astronomical tide, while the water actually present at a coast can also be affected by weather and freshwater flow.

NOAA notes that wind, atmospheric pressure and river flow can cause significant departures from astronomical tide predictions. Its FAQ likewise says prediction accuracy varies by location and that short-term meteorological effects cannot be predicted by the astronomical tide calculation alone.

Use the table to plan, then check the conditions that matter to the activity

A useful sequence is prediction first, conditions second. Use the tide table to understand the expected tidal cycle, then check current weather, warnings, observed water levels or local access information when those factors affect the decision you are making.

This is especially important when a small height difference changes access to rocks, mudflats, launching points or narrow coastal routes. The tide table can frame the window; it should not be treated as a safety guarantee for a specific place.