It's a clear, sunny October afternoon in Miami Beach. There hasn't been a drop of rain in days. And yet Alton Road is shin-deep in saltwater, drivers are wading to their cars, and a kayaker is paddling down 17th Street. Welcome to a king tide.
What is a king tide, exactly?
Tides are caused by the gravitational pull of the moon and sun on Earth's oceans. A "king tide" is the colloquial name for a perigean spring tide — when the moon is both full or new (aligning sun and moon gravity) and at perigee (its closest point to Earth in its monthly orbit). The result is the highest astronomical tide of the year, typically 1.5–2 feet higher than an average high tide.
Why Florida’s southeast coast gets hit so hard
Three things stack up against Miami:
- Sea level rise. Sea levels around Miami have risen about 8 inches since 1950, and the rate is accelerating. What was a high tide in 1980 is now a flooding tide.
- Porous limestone. Miami sits on Oolitic limestone, which acts like a sponge. Seawalls and pumps can hold back the surface, but water just bubbles up through storm drains and lawns from below.
- Flat, low-lying geography. Most of Miami Beach sits less than 5 feet above sea level. There's no slope to drain it.
When to expect them
King tides peak in September, October, and November, with the highest events usually in mid-to-late October. Floodi's own king tide calendar shows the specific upcoming dates with the highest predicted tides, sourced live from NOAA — no need to go dig through NOAA's or the City of Miami Beach's own sites for the numbers.
Which neighborhoods flood first
- Miami Beach — Alton Road, Indian Creek, Sunset Harbour
- Brickell — along South Miami Avenue and the Miami River
- Coconut Grove — Bayshore Drive, Kennedy Park
- Key Biscayne — Crandon Boulevard at high tide
- Florida Keys — US-1 in Key Largo, Big Pine, and Marathon
How to avoid king-tide flooding
Open the live Miami flood map before you head out. Floodi shows real, neighbor-reported flooding right now — not predictions. Save your commute as a watched zone and you'll get an alert the moment a king tide closes a road on your route.
And whatever you do, don't drive through saltwater. It will eat your brake lines, your wheel bearings, and your wiring harness — and a $40 Uber is cheaper than a $4,000 repair.