King Tides: Understanding the Highest Tides of the Year

King tides are the highest high tides and lowest low tides of the year, occurring when the sun and moon align and come closest to Earth. The gravitational pull is strongest during perigee (closest moon approach) combined with new or full moon phases. These extreme tides typically occur 1-2 times per year, usually in winter for the Northern Hemisphere. The term originated in Australia and New Zealand and has become standard worldwide.

King tides are entirely predictable and natural, but their impact grows each year as baseline sea levels rise. What was a king tide 30 years ago is now a moderately high tide. Many coastal communities organize volunteer king tide photo documentation events, where residents photograph water levels at landmarks during peak tides. These images provide powerful visual evidence of sea level rise.

The California King Tides Project, for example, has been running since 2010 and has documented dramatic changes. Scientists use king tides as a preview of future permanent conditions: a king tide today approximates what average high tide will look like in 2050 under most sea level rise projections..