Hawai‘i and Pacific Islands King Tides Project  >>  What is a King Tide?

What is a King Tide?

King Tides are the highest astronomical tides of the year

King tides are the highest astronomical tides of the year. The scientific term for a King Tide is a perigean spring tide. King Tides in the Hawaiian Islands tend to occur during the summer (e.g., July and August) and winter months (e.g., December and January) in conjunction with new moons and full moons. We see King Tides when:

  • The moon is at its closest point to the Earth in its monthly orbit. So the gravitational pull is stronger
  • And, the sun the moon and the Earth are in alignment. Which means that the sun and moon’s individual gravitational pulls work together, producing the highest high tides of the year, or the King Tides of the year.

King Tides, or the highest high tides of the year, are a unique coastal hazard. The timing of these extreme water level events can be anticipated through the use of tidal predictions yet their impacts (e.g.,
coastal flooding and inundation in low lying areas) can have devastating consequences for coastal inhabitants, particularly when combined with severe weather or high wave events. It is a common misconception that king tides are the result of man-made climate change. When in reality, they are not byproducts of climate change, rather they are windows for us to see a what the future of sea level rise from global climate change might look like along our coastlines.

With future sea level rise we can expect more frequent high tide flooding and monthly and even daily high tides exceeding coastal inundation thresholds.