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Find the period over which tidal observations were analysed to produce our tide predictions.

How to calculate the times and heights of and between high and low waters.

Unusually high or low barometric pressure, or prolonged periods of strong winds, can mean the actual sea level is higher or lower than the predicted height.

Until quite recently the use of float gauges was the most common method of measuring and recording sea levels.

New Zealand and Australia have rights over areas of ocean called their Exclusive Economic Zones (EEZ).

Download New Zealand’s maritime boundaries

Standards and specifications for carrying out hydrographic surveys for safety of navigation, and the benefits of hydrographic survey data.

Tidal levels for standard ports, information on reading tide predictions, and the standard port datum descriptions for New Zealand ports.

Data about the marine environment which helps us understand how to protect our biodiversity and ecosystems.

Information on applications to undertake marine scientific research (MSR).

Find out about tide prediction formats and how to interpret the values.

Find New Zealand's standard port chart datums. These are the datums used for stating the depths of the sea on nautical charts, including the level of the water at ports.

New Zealand's tidal regime is semi-diurnal, so on most days two high and two low tides occur at any location.

Learn about tidal theory and the different types of tides around New Zealand.

Finding and accessing data facilitates its reuse.