Accuracy of tide predictions
We encourage you to verify the accuracy of our tide predictions. By doing so you can decide if our information is worth your consideration, and you can also become familiar with certain common problems and pitfalls.
You may want to compare our predictions with another source of tide predictions. Or you can compare with actual water-level measurements made by others, or with your own direct observations.
To compare with another source, first select a tide station of interest. Find the station on this website, either by browsing the world chart or by using the Search button. Find the station in your other source, such as published tide tables, or on another website you consider to be trustworthy.
You can compare times of high and low tides, or you can compare the predicted water levels.
Time of high or low tide
To compare high and low tide times, first select a date of interest. Check the time-zone used by the other source. Often this will be local time (standard time or daylight savings time) at the station. On this website set ☰ Time - Time zone to match.
Then compare the high or low tide times, and decide for yourself if the difference is reasonable. Expect to see good agreement for coastal tide stations with a high tidal range. You will typically see better agreement at dates near spring tides. Near neap tides the high and low tides are usually less distinct.
If the times don't agree at all, double-check the time zone and the date match, for the two sources. Consider daylight-savings time. If the result still makes no sense you could try another tide station, or try another source.
Water level
If you wish to compare predicted water levels, not just the high/low tide times, you will also need to match the height unit and the height datum. The height unit (feet or metres) used by the other source will usually be obvious, set ☰ Tide height - Height unit to match.
Height datum means the zero-reference of the water level. The height datum used by the other source may not be obvious, you may have to guess. Each country typically has a preferred datum. MLLW or LAT are plausible guesses for coastal stations. Open-ocean stations may use MSL or the level of the sea-bed. This website allows you to choose the height datum, see the options available under ☰ Tide height - Height datum.
accuracy last updated 2023-06-14 visit oceantide.io