Boston will see some high tides this fall. How high? Wicked high.

King tides, or “wicked high tides” as the Stone Living Lab on Boston Harbor calls them, happen when the moon’s phases and orbit align perfectly. The moon’s orbit around the Earth is more of an oval shape than a perfect circle, and when the moon is closest, it’s in “perigee,” — hence the scientific name “perigean spring tides.”

When the moon is so much closer to the Earth than the Sun, its pull is stronger, according to the lab. Combined with a new moon, where the Earth, Sun, and Moon all line up, the ocean’s tides are two to four feet higher than normal.

This graphic from the NOAA shows how perigean spring tides happen. – NOAA

The phenomenon happens predictably a few times each year, and Bostonians can experience it f

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