King Tides are the highest predicted non-storm high tide events that occur along the Oregon Coast each year. This naturally occurring phenomenon is driven by celestial mechanics, temporarily raising the ocean’s water level far above the average daily high tide. These tides are not caused by weather, but they offer a clear glimpse into how rising sea levels affect coastal communities and infrastructure. They are the most significant gravitational tides of the year.
The Astronomical Mechanism
King Tides result from the maximum combined gravitational pull from the Moon and the Sun. Tides generally rely on the alignment of the Earth, Moon, and Sun, which happens twice a month during the New and Full Moon phases, creating spring tides. King Tides require a more precise alignment for an even stronger effect. This occurs when the Moon is at perigee—its closest point to Earth—simultaneously with a New or Full Moon alignment.
The Sun plays a substantial role in amplifying this gravitational force. Earth’s orbit is elliptical, and the planet reaches perihelion—its closest point to the Sun—in early January each year. When the Moon, Earth, and Sun align while the Moon is at perigee and the Earth is near perihelion, the gravitational forces combine. This produces the highest possible predicted tide, officially termed a perigean spring tide, which is entirely predictable and scheduled well in advance.
The Annual Schedule for King Tides
King Tides are a consistent feature of the Oregon Coast’s winter season, typically occurring in a sequence across late fall and early winter months. The highest tide sequences of the year are concentrated during this period, generally spanning November, December, and January. This timing is directly influenced by the Earth’s annual orbit. The planet is closest to the Sun near the start of the calendar year, maximizing the solar gravitational contribution to the tide. The precise dates shift annually, based on the lunar calendar and the exact timing of the Moon’s perigee.
A typical King Tides season on the Oregon Coast includes three separate events, often spanning November, December, and early January. These dates are published months in advance, allowing coastal residents and visitors to prepare for the unusually high water levels. Specific, current-year tide charts and schedules are available through resources like NOAA tide tables. Although astronomical conditions for high tides occur throughout the year, the most dramatic tides visible along the Oregon coast are reliably found during these specific winter windows.
Navigating Coastal Impacts and Safety
The volume of water during a King Tide period leads to noticeable impacts along the Oregon coastline. These extreme high tides temporarily inundate low-lying areas, including beaches, dune systems, and coastal access points. Seawater may push further up estuaries and rivers, causing temporary flooding in marshlands and impacting coastal infrastructure. Waves often crash over seawalls or reach areas that remain dry for the rest of the year.
Safety is paramount during these events, as high water levels combine with winter storm swells to create hazardous conditions. The ocean’s energy is capable of rolling large pieces of driftwood, which can be deadly if a person is struck. The United States Coast Guard warns the public about the danger of sneaker waves—unexpectedly large waves that surge far up the beach. Observe King Tides from elevated, set-back locations like coastal viewpoints or bluffs. Never turn your back on the ocean, and avoid walking on jetties or low-lying beaches during the peak high tide.