National Weather Service Marine Forecast FZUS52 KKEY

FZUS52 KKEY 211415
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
1015 AM EDT Mon Sep 21 2026

Florida Bay, Hawk Channel and Straits of Florida from Ocean Reef to south of Dry Tortugas, and the extreme southeastern Gulf of America, including The Florida Keys National Marine Sanctuary

Seas are given as significant wave height, which is the average height of the highest 1/3 of the waves. Individual waves may be more than twice the significant wave height.

The Wave Detail section highlights the period and direction of origin for the highest-energy waves, as well as any long-period swells moving in a different direction than the wind.

GMZ005-220215
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas 1015 AM EDT Mon Sep 21 2026

SYNOPSIS

Unsettled weather will persist through much of today, especially across the Southeast Gulf waters. Breezes outside of convection will generally remain light to gentle with brief periods of moderate breezes occurring at times, mainly in the evening and overnight hours. Towards the end of the week, breezes will shift more northerly as a frontal boundary gradually pushes southward across coastal waters of the Florida Keys. Seas will also start to build by the end of the week and into the weekend as northeasterly swell increases in the wake of the frontal boundary, especially in the Straits of Florida.

The Approximate Shoreward Edge of the Gulf Stream as of September 15, 2026...

64 NM south-southeast of Dry Tortugas Light, on Loggerhead Key 40 NM south-southeast of Cosgrove Shoal Light, off the Marquesas Keys 36 NM south-southeast of Sand Key Light, off Key West 35 NM southeast of Looe Key, off Big Pine Key 28 NM southeast of Sombrero Key Light, off Marathon 15 NM east-southeast of Alligator Reef Light, off Islamorada 8 NM east-southeast of Molasses Reef Light, off Key Largo 5 NM east-southeast of Carysfort Reef Light, off Ocean Reef

Gulf Stream Information Courtesy of the Naval Oceanographic Office.

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GMZ031-220215
Florida Bay including Barnes Sound, Blackwater Sound, and Buttonwood Sound
1015 AM EDT Mon Sep 21 2026

THIS AFTERNOON
South to southwest winds near 10 knots, decreasing to 5 to 10 knots. Bay waters a light chop, becoming smooth to a light chop. A chance of showers with a slight chance of thunderstorms.

TONIGHT
Southeast to south winds 5 to 10 knots. Bay waters smooth to a light chop. Showers likely with a chance of thunderstorms.

TUESDAY
South winds 5 to 10 knots. Bay waters smooth to a light chop. Showers likely with a chance of thunderstorms.

TUESDAY NIGHT
South winds 5 to 10 knots. Bay waters smooth to a light chop. Showers likely with a chance of thunderstorms.

WEDNESDAY
South winds 5 to 10 knots. Bay waters smooth to a light chop. Showers with a chance of thunderstorms.

WEDNESDAY NIGHT
East to southeast winds near 5 knots. Bay waters smooth. Showers likely with a chance of thunderstorms.

THURSDAY
East to southeast winds near 5 knots, becoming south. Bay waters smooth. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
Northwest to north winds near 5 knots. Bay waters smooth. A slight chance of showers and thunderstorms.

FRIDAY
North to northeast winds near 5 knots, becoming southeast to south. Bay waters smooth. Showers likely with a chance of thunderstorms.

FRIDAY NIGHT
North winds near 5 knots. Bay waters smooth. A chance of showers and thunderstorms.

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GMZ032-035-220215
Bayside and Gulfside from Craig Key to west end of Seven Mile Bridge
Gulf of America from west end of Seven Mile Bridge to Halfmoon Shoal out to 5 Fathoms
1015 AM EDT Mon Sep 21 2026

THIS AFTERNOON
South to southwest winds near 10 knots, decreasing to 5 to 10 knots. Seas around 1 foot. Nearshore waters a light chop, becoming smooth to a light chop. A chance of showers with a slight chance of thunderstorms.

TONIGHT
Southeast to south winds 5 to 10 knots, becoming 10 to 15 knots. Seas around 1 foot. Nearshore waters smooth to a light chop, becoming a light to moderate chop. Showers likely with a chance of thunderstorms.

TUESDAY
South winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. Showers likely with a chance of thunderstorms.

TUESDAY NIGHT
South winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. Showers likely with a chance of thunderstorms.

WEDNESDAY
South winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. Showers with a chance of thunderstorms.

WEDNESDAY NIGHT
Southeast to south winds near 5 knots. Seas 1 foot or less. Nearshore waters smooth. Showers likely with a chance of thunderstorms.

THURSDAY
Southeast to south winds near 5 knots. Seas 1 foot or less. Nearshore waters smooth. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
Southwest to west winds near 5 knots, becoming northwest to north. Seas 1 foot or less. Nearshore waters smooth. A chance of showers and thunderstorms.

FRIDAY
North winds near 5 knots. Seas 1 foot or less. Nearshore waters smooth. A chance of showers and thunderstorms.

FRIDAY NIGHT
North winds near 5 knots. Seas 1 foot or less. Nearshore waters smooth. A chance of showers and thunderstorms.

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GMZ042>044-220215
Hawk Channel from Ocean Reef to Craig Key out to the reef
Hawk Channel from Craig Key to west end of Seven Mile Bridge out to the reef
Hawk Channel from west end of Seven Mile Bridge to Halfmoon Shoal out to the reef
1015 AM EDT Mon Sep 21 2026

THIS AFTERNOON
South to southwest winds 10 to 15 knots early, decreasing to 5 to 10 knots. Seas 1 to 3 feet. Nearshore waters a light to moderate chop, becoming smooth to a light chop. A chance of showers with a slight chance of thunderstorms.

TONIGHT
Southeast to south winds 5 to 10 knots, increasing 10 to 15 knots. Seas 1 to 2 feet. Nearshore waters smooth to a light chop, becoming a light to moderate chop. Showers likely with a chance of thunderstorms.

TUESDAY
South winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. Showers likely with a chance of thunderstorms.

TUESDAY NIGHT
South winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. Showers likely with a chance of thunderstorms.

WEDNESDAY
South winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. Showers with a chance of thunderstorms.

WEDNESDAY NIGHT
Southeast winds near 5 knots. Seas around 1 foot. Nearshore waters smooth. Showers likely with a chance of thunderstorms.

THURSDAY
Southeast winds near 5 knots. Seas around 1 foot. Nearshore waters smooth. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
South winds near 5 knots, becoming northwest. Seas around 1 foot. Nearshore waters smooth. A chance of showers and thunderstorms.

FRIDAY
North to northeast winds near 5 to 10 knots knots. Seas around 1 foot. Nearshore waters smooth. A chance of showers and thunderstorms.

FRIDAY NIGHT
North winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth. A chance of showers and thunderstorms.

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GMZ052>055-072>075-220215
Straits of Florida from Ocean Reef to Craig Key out 20 NM
Straits of Florida from Craig Key to west end of Seven Mile Bridge out 20 NM
Straits of Florida from west end of Seven Mile Bridge to south of Halfmoon Shoal out 20 NM
Straits of Florida from Halfmoon Shoal to 20 NM west of Dry Tortugas out 20 NM
Straits of Florida from Ocean Reef to Craig Key 20 to 60 NM out
Straits of Florida from Craig Key to west end of Seven Mile Bridge 20 to 60 NM out
Straits of Florida from west end of Seven Mile Bridge to south of Halfmoon Shoal 20 to 60 NM out
Straits of Florida from Halfmoon Shoal to 20 NM west of Dry Tortugas 20 to 60 NM out
1015 AM EDT Mon Sep 21 2026

THIS AFTERNOON
South to southwest winds 10 to 15 knots, becoming southeast to south 5 to 10 knots late. Seas 2 to 3 feet. Wave Detail: Southeast to south 1 foot at 3 seconds. A slight chance of showers and thunderstorms.

TONIGHT
Southeast winds 5 to 10 knots, becoming south and increasing 10 to 15 knots. Seas 1 to 2 feet. Wave Detail: East to southeast 1 foot at 3 seconds. A chance of showers and thunderstorms.

TUESDAY
South winds 5 to 10 knots. Seas 1 to 2 feet. Wave Detail: Southeast 1 foot at 3 seconds. Showers likely with a chance of thunderstorms.

TUESDAY NIGHT
Southeast to south winds 5 to 10 knots. Seas 1 to 2 feet. Showers likely with a chance of thunderstorms.

WEDNESDAY
South winds 5 to 10 knots. Seas 1 to 2 feet. Showers with a chance of thunderstorms.

WEDNESDAY NIGHT
Southeast winds 5 to 10 knots. Seas 1 to 2 feet. Showers likely with a chance of thunderstorms.

THURSDAY
Southeast winds 5 to 10 knots. Seas 1 to 2 feet. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
East to southeast winds near 5 knots, becoming southwest to west. Seas around 1 foot. A chance of showers and thunderstorms.

FRIDAY
North winds near 5 to 10 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.

FRIDAY NIGHT
North winds near 5 to 10 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.

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GMZ033-034-220215
Gulf of America from East Cape Sable to Chokoloskee 20 to 60 NM out and beyond 5 fathoms
Gulf of America including Dry Tortugas and Rebecca Shoal Channel
1015 AM EDT Mon Sep 21 2026

THIS AFTERNOON
South to southwest winds 5 to 10 knots. Seas around 1 foot. Wave Detail: South 1 foot at 3 seconds. A chance of showers with a slight chance of thunderstorms.

TONIGHT
Southeast to south winds 5 to 10 knots. Seas around 1 foot. Wave Detail: Southeast to south 1 foot at 3 seconds. Showers likely with a chance of thunderstorms.

TUESDAY
South winds 5 to 10 knots. Seas around 1 foot. Wave Detail: Southeast to south 1 foot at 3 seconds. Showers likely with a chance of thunderstorms.

TUESDAY NIGHT
Southeast to south winds 5 to 10 knots. Seas around 1 foot. Showers with a chance of thunderstorms.

WEDNESDAY
South winds 5 to 10 knots. Seas around 1 foot. Showers with a chance of thunderstorms.

WEDNESDAY NIGHT
Southeast to south winds 5 to 10 knots. Seas around 1 foot. Showers likely with a chance of thunderstorms.

THURSDAY
Southeast to south winds near 5 knots. Seas 1 foot or less. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
East to southeast winds near 5 knots, becoming north to northeast. Seas 1 foot or less. A chance of showers and thunderstorms.

FRIDAY
North to northeast winds 5 to 10 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.

FRIDAY NIGHT
North to northeast winds 5 to 10 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.