What conditions are considered when determining LAT?

The determination of Lowest Astronomical Tide (LAT) is based primarily on astronomical and average meteorological conditions. LAT represents the lowest level to which water can be expected to fall, subject to the influence of astronomical factors such as the gravitational pull of the moon and sun, as well as average meteorological conditions like wind and atmospheric pressure.

These conditions are critical because they provide a baseline from which other tidal datums can be measured. LAT is not influenced by transient weather events or unusual climatic conditions, making it a useful standard for hydrographic surveys, particularly in establishing benchmarks for navigational safety and ensuring that nautical charts are accurate. The emphasis on astronomical and average meteorological conditions helps ensure that the LAT remains a reliable point of reference for navigators and surveyors alike.