King tides is a colloquial term that has become very familiar to us in the Florida Keys, especially later in the autumn, when the twice-daily high tides are the highest of the calendar year.
These extreme tides can cause “sunny day flooding” where roads and parking lots may flood from saltwater intrusion underneath, not from rainfall. If it does rain during king tide events, we can get even more flooding. The peak king tide this year was during the super full moon on Oct. 17, which was also the closest the moon came to Earth in 2024. The final king tides of the year will be associated with the full moon on Friday, Nov. 15 and occur from Nov. 13-20.
The rise in sea level means that coastal flooding has become more frequent. From 1913 to 2023, Key West tidal gauge data shows that the relative sea level has risen by 10.32 inches. The Earth’s tides are caused by the gravitational pull of the moon and the sun. The new moon occurs when the moon is between the Earth and the sun, and the gravitational pull from both amplifies tidal heights because both celestial bodies pull the water toward them.
The same is true during full moons, when the Earth is between the moon and the sun. These are called spring tides. The tide is less extreme outside of new and full moons because the sun and moon compete gravitationally, which are called neap tides. The tide is one giant wave that circumnavigates the globe westward with a crest and a trough of rising and falling water. A solar day is 24 hours; this is the time it takes for the Earth to rotate on its axis. A lunar day is how long it takes the moon to rotate around the Earth, which is 50 minutes longer than a solar day. This is why high and low tides are not at the same time every day — if you look at a tide chart, you will see the rising or falling of the tides is around 50 minutes later each successive day.
King tides bring the highest high tides of the year and the lowest low tides. Boaters must be vigilant and check tide tables; they may need more clearance under bridges or traversing seagrass and sandbars that may be very shallow. In the Florida Keys, we have twice-daily high and low tides that average almost 1.5 feet, and king tides are usually 0.4 feet higher. However, tide tables show predicted tides, and the observed high tides could be 2.5 feet or higher, especially when sustained winds push more water ashore.
Knowing when king tides are occurring is essential because this saltwater is very damaging to bikes and vehicles. There are many free smartphone apps for tide times to avoid flood areas and adjust your driving schedule accordingly. If you drive through tidal floods, wash the undercarriage of your car to remove any saltwater accumulation. If you drive through flooded areas, please note that creating waves can cause additional damage to surrounding landscaping and property. Avoid parking your vehicle in low-lying areas prone to flooding to prevent saltwater damage to your car.
For more information reach out to the Monroe County Extension Office.
Note: Thank you for visiting our website! We strive to keep you informed with the latest updates based on expected timelines, although please note that we are not affiliated with any official bodies. Our team is committed to ensuring accuracy and transparency in our reporting, verifying all information before publication. We aim to bring you reliable news, and if you have any questions or concerns about our content, feel free to reach out to us via email. We appreciate your trust and support!