Charleston Harbor

AMZ340 · Coastal Waters Forecast, National Weather Service Charleston SC · issued Sat, Sep 26, 2:15 AM EDT

Rest of tonight: N winds 5 to 10 kt.

Charleston Harbor on the map

The zone and the zones around it, tinted where a marine warning or advisory is in force. Tap a neighboring zone to open its forecast.

Small Craft Advisory

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Now

The nearest stations reporting each, as of Sat, Sep 26, 3:48 AM EDT.

Wind: NNW 5 kt, gusts 7 kt at CHTS1
Waves: 2.0 ft at 6 s at 41065
Water: 79°F at CHTS1

Alerts in force

No marine warning or advisory is in force for this zone.

What is normally issued here: in the past year NWS Charleston, SC issued 16 Special Marine Warnings, 2 Severe Thunderstorm Watches, 12 Small Craft Advisories for this zone.

The forecast

Coastal Waters Forecast from National Weather Service Charleston SC, issued Sat, Sep 26, 2:15 AM EDT, valid until Sat, Sep 26, 4:00 PM EDT. Wind in knots, seas in feet.

Rest of tonight: N winds 5 to 10 kt.
Saturday: N winds 5 to 10 kt.
Saturday night: NW winds 5 kt.
Sunday: W winds 5 to 10 kt.
Sunday night: SW winds 5 to 10 kt.
Monday: N winds 5 kt, becoming S in the afternoon.
Monday night: SW winds 5 kt.
Tuesday: E winds 5 to 10 kt.
Tuesday night: SE winds 5 kt.
Wednesday: SE winds 5 to 10 kt.
Wednesday night: SE winds 5 to 10 kt.

Unless otherwise noted, waves 1 foot or less.

Charleston Harbor water temperature 78 degrees.

Synopsis

Synopsis for the coastal waters of south coastal South Carolina and north coastal Georgia

High pressure will extend across the region into next week. A strong Nor'easter located well to the northeast of Cape Hatteras will move closer to the Mid-Atlantic States and New England over the weekend into early next week.

Buoys and stations nearby

The latest report from each station within reach of the zone, nearest first. Distances in nautical miles from the middle of the zone.

Station	Distance	Wind	Waves	Water	Air	Pressure	Reported
CHTS1 8665530 - Charleston, Cooper River Entrance, SC	1 nm	NNW 5 kt, gusts 7		79°F		1014.6 hPa	Sat, Sep 26, 3:48 AM EDT
FBIS1 Folly Island, SC	5 nm	WNW 4 kt, gusts 6			62°F	1014.2 hPa	Sat, Sep 26, 4:00 AM EDT
41029 Capers Nearshore, SC (CAP2)	14 nm	N 12 kt, gusts 17		78°F	67°F	1013.8 hPa	Sat, Sep 26, 3:08 AM EDT
41065 Capers Nearshore Waves (CAP2WAVE)	14 nm		2.0 ft at 6 s from ESE	77°F			Sat, Sep 26, 3:43 AM EDT
41076 CHR60WAVE	19 nm		3.3 ft at 6 s from E	79°F			Sat, Sep 26, 3:45 AM EDT
41066 CHR60	19 nm			79°F			Sat, Sep 26, 3:45 AM EDT

The past year

Warnings, watches and advisories the National Weather Service issued for this zone over the past 12 months, from the Iowa Environmental Mesonet’s archive.

Product	Issued	Most recent
Special Marine Warning	16	Thu, Aug 27, 2026, 2:23 AM EDT
Severe Thunderstorm Watch	2	Sat, Sep 5, 2026, 6:30 PM EDT
Small Craft Advisory	12	Thu, Sep 24, 2026, 6:00 AM EDT

What this means

Marine forecasts give wind in knots (1 knot is 1.15 mph) and seas in feet, except the high seas forecasts, which give seas in meters. Seas are the significant wave height, the average of the highest third of the waves; individual waves may be more than twice that. On the Great Lakes the forecast gives waves, not seas. "Wave Detail" splits the seas into the wind waves and each swell, with its direction and period.

Each coastal office writes a Coastal Waters Forecast for the bays, sounds and ocean out to 20 to 60 nautical miles, or on the Great Lakes a Nearshore Marine Forecast within 5 nautical miles of shore; the Open Lakes Forecast covers the rest of each lake. The Ocean Prediction Center and the National Hurricane Center write the Offshore Waters Forecasts out to about 250 nautical miles, and the High Seas Forecasts beyond. Forecasts are issued at least twice a day and updated when they go wrong.

Small Craft Advisory: Winds or conditions hazardous to small boats. The thresholds are set by each NWS region: typically sustained winds or frequent gusts of 20 to 25 knots up to 33 knots, and seas of 5 to 7 feet or more.
Gale Warning: Sustained winds or frequent gusts of 34 to 47 knots, not from a tropical cyclone.
Storm Warning: Sustained winds or frequent gusts of 48 to 63 knots, not from a tropical cyclone.
Hurricane Force Wind Warning: Sustained winds or frequent gusts of 64 knots or more, not from a tropical cyclone.
Special Marine Warning: A thunderstorm or squall over the water with winds or gusts of 34 knots or more, hail of 3/4 inch or more, or a waterspout, for up to two hours.
Hazardous Seas Warning: Wave heights or steepness at or above the office’s warning threshold, when the wind alone does not warrant a warning.
Heavy Freezing Spray Warning: Spray freezing on a vessel at 2 cm (3/4 inch) an hour or more.
Tropical Storm and Hurricane Warnings: Tropical storm (34 to 63 knots) or hurricane (64 knots or more) conditions expected within 36 hours. Watches: possible within 48 hours.

Nearby

Open the live map with marine zones and buoys The hour-by-hour forecast for the middle of the zone Charleston County Area Beaches Every Atlantic Coast zone

Sources

Coastal Waters Forecast CWFCHS from National Weather Service Charleston SC, issued Sat, Sep 26, 2:15 AM EDT. Original at NWS. Buoy reports from the National Data Buoy Center. Past products from the Iowa Environmental Mesonet. Zone outlines from the NWS marine and offshore zone boundaries. Warnings and advisories from the NWS API, read 08:40 UTC. All public domain, from the National Weather Service.