Tide predictions for standard ports are based on continuous observation of tide over a period of at least one year. These predictions are given in feet or meters, with respect to the chart datum for average meteorological conditions. Some examples of primary ports are Bhavnagar, Bombay, Cochin, Manila, Karachi, Singapore, Suez, Port Dickson, etc. Standard ports are marked in bold letters in the Index pages of Admiralty Tide Tables (or Tidal almanac). Tidal predictions are usually made by the Bureau of Meteorology of that country.
Secondary ports (also called Secondary place in some countries like Australia), on the other hand, are ports for which tides have to be calculated, based on a primary port with a similar tidal curve. Some examples of Secondary ports are Rabigh, Porto Novo, Porbandar, Port Cornwalis, Sharjah, The Sandheads (Hugli), etc.
- Admiralty Tide Tables - ATT. Taunton, UK: UKHO - United Kingdom Hydrographic Office. 2010. p. vi.
- "Definitions of tidal terms". LINZ - Land Information New Zealand. Retrieved 1 October 2013.
- "An explanation of tidal information". Cambridge school of navigation. Retrieved 1 October 2013.
- "About us - Australian National Tidal Center" (PDF). Bureau of Meteorology. Retrieved 1 October 2013.
- "Notes and definitions". Tides. Maritime Safety Queensland. Retrieved 1 October 2013.
- "Tides". Terrestrial Navigation. www.thenauticalsite.com. Archived from the original on 8 August 2013. Retrieved 1 October 2013.CS1 maint: BOT: original-url status unknown (link)