Watch out for the ‘wicked high’ king tides this week at Boston Harbor | Boston.com
The tides are scientifically known as perigean spring tides and are caused by a combination of the moon’s orbit and phases.
By Darin Zullo | September 11, 2025
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 or full moon, where the Earth, Sun, and Moon all line up, the ocean’s tides are two to four feet higher than normal.
The phenomenon happens predictably a few times each year, and Bostonians can experience it for themselves with the National Park Service’s High Tide Trail, a walking tour along the coastline. The Stone Living Lab will also have high tide events at Long Wharf throughout the fall starting Thursday. See a full list of events below:
September
- Thursday, Sept. 11, at 2:30 p.m.
October
- Wednesday, Oct. 8, at 12:27 p.m.
- Thursday, Oct. 9, at 1:15 p.m.
- Friday, Oct. 10, at 2:05 p.m.
- Saturday, Oct. 11, at 2:58 p.m.
November
- Wednesday, Nov. 5, at 10:13 a.m.
- Thursday, Nov. 6, at 11:01 a.m.
- Friday, Nov. 7, at 11:52 a.m.
- Saturday, Nov. 8, at 12:45 p.m.
December
- Saturday, Dec. 6, at 11:35 a.m.
- Wednesday, Dec. 3, at 8:58 a.m.
- Thursday, Dec. 4, at 9:49 a.m.
- Friday, Dec. 5, at 10:41 a.m.