A tidal monitoring station in Alaska.
The highest tides in the world can be found in Canada at the Bay of Fundy, which separates New Brunswick from Nova Scotia. At some times of the year the difference between high and low tide in this Bay is 16.3 meters (53.5 feet), taller than a three-story building.
The highest tides in the United States can be found near Anchorage, Alaska, with tidal ranges up to 12.2 meters (40 feet).
At increasing lattitudes (as one moves further from the equator and closer to the poles) there often is a dramatic increase in tidal range.
Tidal highs and lows depend on a lot of different factors. The shape and geometry of a coastline play a major role, as do the locations of the Sun and Moon. Storm systems at sea and on land also shift large quantities of water around and affect the tides. Detailed forecasts are available for high and low tides in all sea ports, but are specific to local conditions.
For more information:
Tides and Water Levels, NOS Education
Tides Online, Center for Operational Oceanographic Products and Services