“When king tides coincide with coastal storms, the impacts can be devastating.” — Florida Sea Grant  

What are King Tides? 

King tides are the highest natural high tides of the year. They are not caused by storms or extreme weather, but by consistent interactions between the Earth, moon, and sun. According to the NOAA, king tides occur when gravitational forces are strongest, creating a tug-of-war between the ocean and the coast. 

The term “king tide” is the commonly used name for what scientists call a perigean spring tide. These tides happen when the moon is at its closest point to Earth in its orbit, known as a perigee, while also aligning with the sun during a new or full moon. When these alignments occur at the same time, the combined gravitational pull increases the height of tides beyond their normal daily ranges. 

In Florida, king tides usually occur a few times each year, most often in the fall. Geographic conditions, such as ocean currents and seasonal changes in sea level, can make these tides even higher. Communities across the state track these events using tide prediction charts, such as those provided by the City of St. Augustine, which help community members prepare for when water levels will be at their peak. Although king tides are a natural and predictable part of the tidal cycle, they are the ceiling of normal tidal conditions. Because of this, they are often used as a reference point for understanding how coastal water levels behave under the strongest gravitational influences. 

Why Do King Tides Matter? 

King tides mark the upper edge of what “normal” water levels look like, and in many Florida communities, that edge is already spilling over. During these tidal events, seawater can invade inland without the extra push from heavy rain or storms, a phenomenon often called sunny-day or nuisance flooding. Streets that are dry for the majority of the year can begin to resemble shallow canals, with water bubbling up through storm drains and pooling across roads, sidewalks, and parking lots. According to Miami Dade County, these high tides can flood low-lying areas, disrupt transportation, and place stress on drainage systems that were not designed to handle water coming from the ocean rather than the sky.

This type of flooding may appear to be minor, or simply a small “nuisance” at first, but its impacts build over time. Saltwater can corrode infrastructure, weaken roadways, and damage underground utilities. It can also seep into local freshwater systems, affecting soil, vegetation, and drinking water. In this way, king tides act like a chronic disease — slowly but persistently showing where coastlines are most vulnerable and where future flooding is likely to occur more frequently. 

The timing of king tides adds another layer of risk for coastal communities. In Florida, they often overlap with peak hurricane season. On their own, king tides raise the baseline of the ocean. When a strong storm arrives on top of that already elevated water level, the effects can multiply quickly. Storm surge, which is the abnormal rise of water generated by a storm, has farther to travel inland when it starts from a higher point. What might have been manageable flooding under normal tidal conditions can become far more destructive when amplified by a king tide. 

Water no longer stays at the edges; it now pushes directly into developed areas, surrounding homes, overtaking roads, and reshaping familiar spaces. Entire neighborhoods can be impacted as floodwater rises higher and moves faster, leaving behind damage that takes far longer to repair than the tide itself takes to recede. 

 What Can You Do? 

The first step in preparing for king tides is awareness. Because these events are predictable, coastal residents can plan by checking local tide forecasts and county resources. Many Florida communities publish king tide schedules and maps that show areas most prone to flooding, such as those provided by the City of St. Augustine, Crystal River, Fort Lauderdale, and Palm Beach County. By knowing approximately when and where water levels will peak, residents can avoid driving through flooded streets, move vehicles to higher ground, and take precautions to protect homes and businesses. 

Small actions such as clearing storm drains near homes can help water flow more efficiently, while using sandbags or other temporary barriers can limit the amount of water that enters buildings. In areas that experience consistent flooding, some residents and communities are beginning to adapt more permanently by elevating structures and improving drainage systems. The restoration and conservation of natural barriers such as oyster reefs, mangroves, and salt marshes can also help to mitigate the effects of extreme flooding events.   

For those who do not live along the coast, king tides may feel distant, but their impacts connect inland as well. Finding ways to support coastal communities can take many forms, from advocating for resilient infrastructure and sustainable urban planning to staying informed about how sea level rise affects different regions.  

King tides create a moment when the boundary between land and water becomes temporarily blurred, revealing just how fragile that line can be and how quickly it can shift. 

Information from: NOAA, Florida Sea Grant, Miami-Dade County, City of St. Augustine, Palm Beach County