King tides are the highest predicted astronomical tides of the year, produced when the sun, moon, and Earth line up in a way that adds their gravitational pull together rather than partly canceling it out. They are not storms and not a form of sea-level rise on their own, but a predictable, calendar-driven event that Southern California beaches see a handful of times a year, most often in winter. Because king tides push water higher than any other routine high tide, they double as a preview of what an average day could look like decades from now as sea level continues to rise.
What Is a King Tide?
A king tide is not an official scientific term but a widely used name for the year's highest predicted astronomical tides, tracked by NOAA Tides and Currents at named tide stations up and down the coast. The tide itself is entirely predictable, calculated years in advance from the orbital mechanics of the sun, moon, and Earth, which sets it apart from a storm surge or a tsunami, both of which depend on unpredictable weather or seismic events layered on top of whatever the tide happens to be doing that day.
Confusing a king tide with a storm surge is one of the most common mistakes in coastal reporting. A king tide will happen on its predicted date whether the sky is clear or stormy. A storm surge, by contrast, is extra water pushed onshore by wind and low pressure during an active weather system and can occur at any point in the tide cycle. The most dramatic coastal flooding happens when both occur at once, which the sections below cover in more detail.
Why Do the Highest Tides Occur?
Ordinary daily tides come from the moon's gravity pulling on the ocean as Earth rotates, with the sun adding a smaller pull of its own. Twice a month, at new moon and full moon, the sun and moon align with Earth and their gravitational pulls combine, producing what astronomers call a spring tide, a period of higher-than-average high tides and lower-than-average low tides. Not every spring tide is a king tide, though. The moon's orbit is not a perfect circle, so its distance from Earth varies, and when a spring tide lines up with the moon at its closest approach, called perigee, and Earth at its closest approach to the sun, called perihelion, the combined pull is at its strongest for the year.
| Event | Predictable? | What drives it |
|---|---|---|
| Ordinary high tide | Yes, daily | Moon and sun gravity, twice-daily cycle |
| King tide | Yes, calendar-based | Sun, moon, and Earth alignment at closest approach |
| Storm surge | No, weather-dependent | Low pressure and onshore wind pushing extra water inland |
When and Where Can Southern California See King Tides?
NOAA publishes station-specific tide predictions years in advance, so the exact date, time, and predicted height of a king tide at any Southern California location is a matter of checking the official record for that station rather than guessing from a general rule. King tide events in Southern California cluster around the winter months, when Earth's orbit brings it closest to the sun, and the highest water at a given station typically occurs within a short window around sunrise or sunset rather than at a fixed clock time every year.
Every coastal community sees king tides, but the visible effect depends heavily on local geography. Low-lying, gently sloped shoreline near Long Beach and harbor areas near San Pedro can see water reach parking lots, boat ramps, and low walkways that stay dry the rest of the year, while steeper, rockier stretches near Malibu show the same extra water as a smaller vertical rise against the cliffs. Always check the exact predicted date, time, and height for the tide station nearest your destination rather than assuming a single Southern California-wide schedule.
How Can Weather and Waves Increase Impacts?
The astronomical prediction is only the baseline. Low atmospheric pressure allows the ocean surface to rise slightly, onshore wind piles water against the coast, and swell arriving from a distant storm adds wave run-up on top of whatever the tide gauge itself reads. When several of these factors stack on top of an already-elevated king tide, the observed water level at the shoreline can run noticeably higher than the astronomical prediction alone would suggest, which is why NOAA's predicted tide height and the actual water people see at the beach are related but not identical numbers.
Beach orientation and slope also shape the outcome. A wide, gently sloped beach absorbs extra water over a larger area, while a narrow beach backed by a seawall, road, or bluff has less room to spread that water out, so the same combination of tide and swell can produce very different results a few miles apart. The mechanics of how waves and storms erode and reshape that shoreline over time are covered in coastal erosion in Southern California, and the large, unpredictable waves that can arrive independent of the tide cycle entirely are covered in what are rogue waves.
Heavy rain can compound the same high-water setup by filling channels and storm drains just as the elevated ocean slows their discharge. The local watershed differences are clear when comparing flash flooding in Santa Monica with flash flooding in Ventura, where larger rivers carry runoff to the coast.
Are King Tides Caused by Climate Change?
No. King tides are an astronomical cycle driven by the relative positions of the sun, moon, and Earth, and they would occur on the same schedule with or without climate change. What climate change does is raise the baseline sea level that every tide, including a king tide, builds on top of. As mean sea level rises over decades, the same astronomical king tide reaches a higher absolute water level than it would have reached at the same point in the lunar cycle a generation ago.
This is why coastal scientists and agencies use king tides as a preview tool rather than proof of anything from a single flooded sidewalk or parking lot. A king tide shows, several times a year under ordinary clear-sky conditions, roughly where the water could sit on an average day once sea level rises enough to match it permanently. One flooded location on one king tide day is a data point, not a trend, but the recurring pattern across many king tide events over years is exactly the kind of evidence coastal planners use to identify vulnerable low-lying areas.
How Can People Observe King Tides Safely?
The safest way to see a king tide is from a stable public viewpoint in daylight, well back from cliff edges, seawalls, and the surf line itself, since the same conditions that raise the tide can also bring larger waves and stronger rip currents. Treat any king tide outing the same way you would treat a day with an active NWS beach hazard advisory: check conditions before you go, keep well back from the waterline, and never turn your back on the ocean, particularly on rocks or jetties that can be reached by an unexpectedly large wave.
Pair the official NOAA tide table for your nearest station with the current high-surf and coastal-flood alerts from NWS Los Angeles/Oxnard or NWS San Diego before heading to the coast, since a king tide day with an active high-surf event is a meaningfully different, and more hazardous, situation than a calm king tide day. Waterspouts that occasionally form over the Southern California coast are a separate, storm-driven hazard covered in what are waterspouts, worth knowing about if you plan to spend extended time watching the water.
King tides are one of the few coastal events in Southern California you can put on a calendar years in advance, and that predictability is exactly what makes them useful: a low-risk chance to see, in person, roughly where the ocean could sit on an ordinary day as sea level continues to rise. Before heading out to watch one, check the exact predicted time and height for your nearest NOAA tide station, confirm there is no active high-surf or coastal-flood alert, and check current conditions for Santa Monica, Malibu, or your chosen stretch of coast on WeatherEscape before you go.