Your location is also important as due to all the factors mentioned above and other physical elements, such as the shape of the shoreline, small bays and estuaries which may alter the magnitude and the tide types you may see which are broken down into three, semidiurnal, mixed semidiurnal, and diurnal tides. Tide clocks are most effective when used in semidiurnal tidal areas (primarily on the Atlantic Coast), which experience two high and two low tides, approximately equal in size every lunar day. These areas are indicated with red highlights on the image in this post.

Given this, tide clocks can be set up at any high tide but ideally should be set up (or reset) at high tide during the full moon, and when done correctly usually any discrepancy during the lunar cycle will be less than 30 minutes and therefore will be unnoticeable. Typically, only four or five days each month will have a difference as great as an hour and the clocks may need occasional corrections which ideally should also be completed at high time on a full moon.