Charleston floods on sunny days now. In 2024 the harbor crossed flood stage 54 times — the 7th-worst year on record — and most of those weren't storms at all. They were king tides: the handful of days each year when the moon's orbit and seasonal high water stack up and push the harbor over the seawalls, into the storm drains, and up through the ground. If you live on the peninsula, in West Ashley, or anywhere near a tidal creek on James Island, these dates belong on your refrigerator. Here is every remaining king tide window for 2026, what the water levels actually mean, and what to do if the tide reaches your home.
The 2026 King Tide Dates for Charleston
Predicted king tide windows at the Charleston Harbor gauge (NOAA station 8665530), per NOAA tide predictions and the SC Sea Grant Consortium's Tidelines calendar:
| 2026 Window | Status | Notes |
|---|---|---|
| April 18 | Past | Single-day window |
| May 15–18 | Past | Four-day window |
| June 14–16 | Past | — |
| July 13–14 | Past | — |
| August 11–12 | NEXT | Falls in peak hurricane season — any offshore system adds to it |
| September 29–30 | Upcoming | Fall windows run highest |
| October 10–11 | Upcoming | Perigean tide — historically among the year's highest |
| October 26–29 | Upcoming | Four-day window |
| November 24–27 | Upcoming | Thanksgiving week — plan around travel |
Two things to remember about these predictions: they assume calm weather — onshore wind, offshore storms, or heavy rain on top of a king tide raises the real number well past the prediction. And fall windows run worst, because seasonal ocean warming adds inches to every tide from September through November.
What the Numbers Mean: Charleston's Flood Stages
- 7.0 ft MLLW — minor flooding. "Nuisance" flooding: water in the lowest streets and parking lots, storm drains backing up. Nuisance is the official word; if it's your car or your crawl space, it's damage.
- 7.5 ft — moderate flooding. Multiple streets impassable downtown and in West Ashley; water approaches ground-floor level in the lowest-lying homes and garages.
- 8.0 ft — major flooding. Widespread street flooding, vehicles flooded, water entering structures. For scale: Hurricane Idalia's 2023 tide hit 9.23 ft — fifth-highest ever recorded — but pure king tides have crossed 8 ft with no storm in sight.
Sea level at Charleston is more than a foot higher than a century ago, and the City's own Water Plan projects as many as ~170 flood events a year by 2050. The trend line only points one way — which is why we publish this calendar every year.
Where the Water Shows Up First
Every Charlestonian knows the greatest hits: the Crosstown (Septima P. Clark Parkway) — now the subject of a $154M drainage-tunnel project — the City Market, East Bay Street, and Morrison Drive. But king tide water isn't just a peninsula problem. West Ashley's Church Creek basin has flooded so repeatedly the city bought out and demolished an entire block of Shadowmoss townhomes. On James Island, homes along the tidal creeks watch water climb the yard well before it touches the road. And on Folly Beach, Isle of Palms, and the marsh edges of Johns Island, king tides arrive from two directions — the beach and the marsh behind you.
If you're not sure how your street behaves, the City of Charleston's TIDEeye map shows real-time flooded-street reports, and the MyCoast SC King Tides project collects photo reports from every window — both worth bookmarking alongside the NOAA gauge.
The Insurance Trap Hiding in a Sunny-Day Flood
Tidal flooding is a flood claim, not a homeowners claim. Water that rises from outside — tide, surge, overwhelmed drainage — is excluded from standard homeowners policies. It's covered only by flood insurance (NFIP or private), which is a separate policy with a 30-day waiting period. If a king tide has ever come within a foot of your slab, price a flood policy long before the fall windows. One silver lining for this county: Charleston-area communities rank among the best in the nation in FEMA's Community Rating System — unincorporated Charleston County's Class 2 rating earns up to a 40% NFIP discount — so coverage here costs less than most coastal homeowners assume.
If the Tide Reached Your Garage, Crawl Space, or Floors
Tidewater is not clean water. By the time it's inside your home it has passed through storm drains, marsh mud, and — in parts of the metro with documented sewer overflows — worse. We treat tidal intrusion as contaminated (Category 3) water: extraction, removal of what soaked, disinfection, then verified drying (why floodwater is handled like sewage). Salt adds its own problem — it corrodes fasteners, wicks into concrete and framing, and keeps pulling moisture from the air long after the water is gone.
- Don't wait for it to drain and dry on its own. In Charleston humidity, a tide-wet crawl space becomes a mold remediation in days — here's what happens under raised homes.
- Photograph everything before you touch anything — the water line, the contents, the yard. Flood claims live and die on documentation.
- Kill power to flooded circuits before wading into a garage or crawl space.
- Call while it's still wet. The first hours decide whether this is an extraction or a rebuild — the full sequence is in our first-24-hours guide.
Track It Live
The three tools we actually use: the NOAA Charleston Harbor gauge (station 8665530) for predictions and real-time water level, the City's TIDEeye flooded-streets map, and MyCoast SC for community king tide photo reports. Our crews monitor coastal flood advisories for Charleston, Berkeley, and Dorchester counties around the clock — when an advisory posts for a king tide window, we're staged for it, the same as any named storm.
The Short Version
Next window: August 11–12. Then September 29–30, October 10–11, October 26–29, and November 24–27. Minor flooding starts at 7.0 ft at the harbor gauge. Tidal water in your home is a flood-policy claim with a 30-day purchase wait — check your coverage now, not in October. And if a king tide beats you to it, call (843) 790-5769 while the water's still standing — locally owned on James Island, we're on the tide's side of the bridges.