National Weather Service Marine Forecast FZUS52 KKEY

FZUS52 KKEY 010239
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
1039 PM EDT Mon Aug 31 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.

GMZ005-011445
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas 1039 PM EDT Mon Aug 31 2026

SYNOPSIS

The western periphery of an Atlantic high remains in control of the Keys for the next several days. Therefore, expect continued peaking and lulling breezes. The direction will also shift over the next few days with east to southeasterly breezes overnight and in the morning with northeast to east breezes late afternoon and evening. In addition, the overall flow will keep deep moisture in place across the region with daily chances of showers and thunderstorms. Locally hazardous winds and seas are expected in the vicinity of thunderstorm activity.

The Approximate Shoreward Edge of the Gulf Stream as of August 26, 2026...

32 NM south of Dry Tortugas Light, on Loggerhead Key 9 NM south-southeast of Cosgrove Shoal Light, off the Marquesas Keys 7 NM south-southeast of Sand Key Light, off Key West 6 NM south-southeast of Looe Key, off Big Pine Key 7 NM south-southeast of Sombrero Key Light, off Marathon 4 NM southeast of Alligator Reef Light, off Islamorada 1 NM west-northwest of Molasses Reef Light, off Key Largo 1 NM east-southeast of Carysfort Reef Light, off Ocean Reef

Gulf Stream Information Courtesy of the Naval Oceanographic Office.

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GMZ031-011445
Florida Bay including Barnes Sound, Blackwater Sound, and Buttonwood Sound
1039 PM EDT Mon Aug 31 2026

OVERNIGHT
Northeast winds near 5 knots, becoming east and increasing to 5 to 10 knots. Bay waters smooth, becoming smooth to a light chop. A chance of showers and thunderstorms.

TUESDAY
East to southeast winds near 5 knots. Bay waters smooth. A chance of showers and thunderstorms.

TUESDAY NIGHT
East winds 5 to 10 knots. Bay waters smooth to a light chop. A chance of showers and thunderstorms.

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

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

THURSDAY
East to southeast winds 10 to 15 knots. Bay waters a light to moderate chop. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
East to southeast winds 10 to 15 knots. Bay waters a light to moderate chop. Showers and thunderstorms likely.

FRIDAY
Southeast winds 5 to 10 knots. Bay waters smooth to a light chop. A chance of showers and thunderstorms.

FRIDAY NIGHT
East to southeast winds 5 to 10 knots. Bay waters smooth to a light chop. A chance of showers and thunderstorms.

SATURDAY
Southeast winds near 5 knots. Bay waters smooth. Showers and thunderstorms likely.

SATURDAY NIGHT
East to southeast winds near 5 knots. Bay waters smooth. A chance of showers and thunderstorms.

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GMZ032-035-011445
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
1039 PM EDT Mon Aug 31 2026

OVERNIGHT
Northeast winds 5 to 10 knots, becoming east. Seas 1 foot or less. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

TUESDAY
East to southeast winds 5 to 10 knots, decreasing to near 5 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

TUESDAY NIGHT
East winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop, becoming smooth. A chance of showers and thunderstorms.

WEDNESDAY
East to southeast winds near 5 knots. Seas 1 foot or less. Nearshore waters smooth. A chance of showers and thunderstorms.

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

THURSDAY
East to southeast 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.

THURSDAY NIGHT
East to southeast winds 10 to 15 knots. Seas around 1 foot. Nearshore waters a light to moderate chop. Showers and thunderstorms likely.

FRIDAY
Southeast winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

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

SATURDAY
Southeast to 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.

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

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GMZ042>044-011445
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
1039 PM EDT Mon Aug 31 2026

OVERNIGHT
Northeast to east winds 5 to 10 knots, becoming east to southeast. Seas around 1 foot. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

TUESDAY
East to southeast winds 5 to 10 knots, becoming east to northeast and decreasing to near 5 knots. Seas around 1 foot. Nearshore waters smooth to a light chop, becoming smooth. A chance of showers and thunderstorms.

TUESDAY NIGHT
East winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

WEDNESDAY
East winds near 5 knots. Seas around 1 foot. Nearshore waters smooth. A chance of showers and thunderstorms.

WEDNESDAY NIGHT
East winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

THURSDAY
East to southeast winds 5 to 10 knots. Seas 1 to 2 feet. Nearshore waters smooth to a light chop. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
East to southeast winds 10 to 15 knots. Seas 1 to 2 feet. Nearshore waters a light to moderate chop. Showers and thunderstorms likely.

FRIDAY
Southeast winds 5 to 10 knots. Seas 1 to 2 feet. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

FRIDAY NIGHT
East to southeast winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

SATURDAY
Southeast winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. A chance of showers and thunderstorms.

SATURDAY NIGHT
Southeast winds near 5 knots. Seas around 1 foot. Nearshore waters smooth. A chance of showers and thunderstorms.

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GMZ052>055-072>075-011445
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
1039 PM EDT Mon Aug 31 2026

OVERNIGHT
Northeast to east winds near 10 knots, becoming east. Seas 1 to 2 feet. Wave Detail: Northeast to east 2 feet at 4 seconds. A chance of showers and thunderstorms.

TUESDAY
East winds 5 to 10 knots. Seas 1 to 2 feet. Wave Detail: East 1 foot at 4 seconds. A chance of showers and thunderstorms.

TUESDAY NIGHT
East winds 5 to 10 knots. Seas 1 to 2 feet. Wave Detail: Northeast to east 2 feet at 4 seconds. A chance of showers and thunderstorms.

WEDNESDAY
East winds near 5 knots. Seas around 1 foot. A chance of showers and thunderstorms.

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

THURSDAY
East to southeast winds 5 to 10 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.

THURSDAY NIGHT
East to southeast winds 10 to 15 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.

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

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

SATURDAY
Southeast winds 5 to 10 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.

SATURDAY NIGHT
East to southeast winds 5 to 10 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.

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GMZ033-034-011445
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
1039 PM EDT Mon Aug 31 2026

OVERNIGHT
Northeast winds 5 to 10 knots, becoming east. Seas 1 foot or less. Wave Detail: Northeast to east 1 foot at 3 seconds. A chance of showers and thunderstorms.

TUESDAY
East to southeast winds 5 to 10 knots, becoming east. Seas 1 foot or less. Wave Detail: East to southeast 1 foot at 3 seconds. A chance of showers and thunderstorms.

TUESDAY NIGHT
Northeast to east winds near 5 knots, becoming east. Seas 1 foot or less. A chance of showers and thunderstorms.

WEDNESDAY
East winds near 5 knots. Seas 1 foot or less. A chance of showers and thunderstorms.

WEDNESDAY NIGHT
East winds 5 to 10 knots. Seas 1 foot or less. A chance of showers and thunderstorms.

THURSDAY
East to southeast winds 5 to 10 knots. Seas around 1 foot. Showers likely with a chance of thunderstorms.

THURSDAY NIGHT
East to southeast winds near 10 knots. Seas around 1 foot. Showers and thunderstorms likely.

FRIDAY
Southeast winds 5 to 10 knots. Seas around 1 foot. A chance of showers and thunderstorms.

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

SATURDAY
Southeast to south winds near 5 knots. Seas 1 foot or less. A chance of showers and thunderstorms.

SATURDAY NIGHT
Southeast winds near 5 knots. Seas 1 foot or less. Showers likely with a chance of thunderstorms.