“King tides” is a non-scientific name for the highest or the lowest tide events in a year. Christine Voss, a research associate at the University of North Carolina’s Institute of Marine Sciences in Morehead City explains.
“So you’re probably aware of spring tides that occur during full moons and new moons. And those tides are even stronger during what’s called perigee. And perigee is when the moon is physically closest to the Earth in its elliptical orbit around the Earth. Therefore, the gravitational pull of the moon and the sun on Earth is greatest in what we call a King Tide”.