Marine Weather and Tide Forecast for Marathon, FL
 | Sunrise 6:43 AM Sunset 8:03 PM Moonrise 4:22 AM Moonset 6:03 PM |
Marine Forecasts
NOTE: Zones updated 4/16/2026. Some zones changed. Use Edit if needed.
GMZ053 Expires:202605160830;;616865 Fzus52 Kkey 152026 Cwfkey
coastal waters forecast for the florida keys national weather service key west fl 426 pm edt Fri may 15 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.
wave detail will include details about the period and direction of origin for the highest energy waves. Long-period swells coming from a different direction than the wind would be included in the wave detail.
gmz052>055-072>075-160830- 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- 426 pm edt Fri may 15 2026
Tonight - East winds 5 to 10 knots, increasing to near 10 knots. Seas around 1 foot, building to 1 to 2 feet. Wave detail: east 1 foot at 2 seconds and northwest 1 foot at 5 seconds. A slight chance of showers and Thunderstorms.
Saturday - East winds 10 to 15 knots. Seas 2 to 3 feet. Wave detail: east 2 feet at 3 seconds. A slight chance of showers and Thunderstorms.
Saturday night - East winds near 15 knots. Seas 3 to 4 feet, occasionally to 5 feet. Wave detail: east 3 feet at 4 seconds. A chance of showers with a slight chance of Thunderstorms.
Sunday - East winds near 15 knots. Seas 3 to 4 feet, occasionally to 5 feet. A chance of showers with a slight chance of Thunderstorms.
Sunday night - East winds 15 to 20 knots. Seas 4 to 5 feet, occasionally to 6 feet. A chance of showers with a slight chance of Thunderstorms.
Monday - East winds near 15 knots. Seas 3 to 5 feet, occasionally to 6 feet. A chance of showers with a slight chance of Thunderstorms.
Monday night - East winds 15 to 20 knots. Seas 4 to 6 feet, occasionally to 7 feet. A slight chance of showers and Thunderstorms.
Tuesday - East winds near 15 knots. Seas 3 to 5 feet, occasionally to 6 feet. A slight chance of showers and Thunderstorms.
Tuesday night - East winds near 15 knots. Seas 3 to 4 feet, occasionally to 5 feet. A slight chance of showers and Thunderstorms.
Wednesday - East winds 10 to 15 knots. Seas 2 to 4 feet, occasionally to 5 feet.
Wednesday night - East winds 10 to 15 knots. Seas 2 to 4 feet, occasionally to 5 feet. A slight chance of showers and Thunderstorms.
coastal waters forecast for the florida keys national weather service key west fl 426 pm edt Fri may 15 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.
wave detail will include details about the period and direction of origin for the highest energy waves. Long-period swells coming from a different direction than the wind would be included in the wave detail.
gmz052>055-072>075-160830- 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- 426 pm edt Fri may 15 2026
GMZ005 Synopsis For Keys Coastal Waters From Ocean Reef To Dry Tortugas 426 Pm Edt Fri May 15 2026
Synopsis - Light to gentle breezes will prevail tonight and Saturday. High pressure developing over the southeast will take root across the western north atlantic over the weekend. As a result, moderate to fresh easterly breezes will peak and lull across the florida keys Sunday through Tuesday.
the approximate shoreward edge of the gulf stream as of may 12 - .
35 nm south of dry tortugas light - .on loggerhead key. 9 nm south of cosgrove shoal light - .off the marquesas keys. 6 nm south of sand key light - .off key west. 7 nm south of looe key - .off big pine key. 6 nm southeast of sombrero key light - .off marathon. 6 nm southeast of alligator reef light - .off islamorada. 4 nm southeast of molasses reef light - .off key largo. 3 nm southeast of carysfort reef light - .off ocean reef.
gulf stream information courtesy of the national weather service in key west based on products from nasa sport and rtofs.
the approximate shoreward edge of the gulf stream as of may 12 - .
35 nm south of dry tortugas light - .on loggerhead key. 9 nm south of cosgrove shoal light - .off the marquesas keys. 6 nm south of sand key light - .off key west. 7 nm south of looe key - .off big pine key. 6 nm southeast of sombrero key light - .off marathon. 6 nm southeast of alligator reef light - .off islamorada. 4 nm southeast of molasses reef light - .off key largo. 3 nm southeast of carysfort reef light - .off ocean reef.
gulf stream information courtesy of the national weather service in key west based on products from nasa sport and rtofs.
7 Day Forecast for Marine Location Near Marathon, FL
NEW! Add second zone forecast
| Vaca Key-Fat Deer Key bridge Click for Map Fri -- 01:43 AM EDT 0.29 feet Low Tide Fri -- 05:21 AM EDT Moonrise Fri -- 06:40 AM EDT Sunrise Fri -- 07:40 AM EDT 1.95 feet High Tide Fri -- 03:05 PM EDT -0.37 feet Low Tide Fri -- 07:02 PM EDT Moonset Fri -- 08:01 PM EDT Sunset Fri -- 09:23 PM EDT 1.18 feet High Tide Tide / Current data from XTide NOT FOR NAVIGATION |
Vaca Key-Fat Deer Key bridge, Florida, Tide feet
| 12 am |
| 0.5 |
| 1 am |
| 0.3 |
| 2 am |
| 0.3 |
| 3 am |
| 0.5 |
| 4 am |
| 0.9 |
| 5 am |
| 1.3 |
| 6 am |
| 1.7 |
| 7 am |
| 1.9 |
| 8 am |
| 1.9 |
| 9 am |
| 1.8 |
| 10 am |
| 1.5 |
| 11 am |
| 1 |
| 12 pm |
| 0.5 |
| 1 pm |
| 0.1 |
| 2 pm |
| -0.3 |
| 3 pm |
| -0.4 |
| 4 pm |
| -0.3 |
| 5 pm |
| 0 |
| 6 pm |
| 0.4 |
| 7 pm |
| 0.7 |
| 8 pm |
| 1 |
| 9 pm |
| 1.2 |
| 10 pm |
| 1.2 |
| 11 pm |
| 1 |
| Moser Channel Click for Map Flood direction 346 true Ebb direction 164 true Fri -- 02:14 AM EDT -1.26 knots Max Ebb Fri -- 05:20 AM EDT 0.00 knots Slack Fri -- 05:22 AM EDT Moonrise Fri -- 06:40 AM EDT Sunrise Fri -- 07:54 AM EDT 1.24 knots Max Flood Fri -- 11:10 AM EDT -0.00 knots Slack Fri -- 02:20 PM EDT -2.09 knots Max Ebb Fri -- 06:10 PM EDT 0.00 knots Slack Fri -- 07:02 PM EDT Moonset Fri -- 08:01 PM EDT Sunset Fri -- 09:44 PM EDT 1.38 knots Max Flood Tide / Current data from XTide NOT FOR NAVIGATION |
Moser Channel, between Molasses and Pigeon Keys (depth 3 ft), Florida Current, knots
| 12 am |
| -0.3 |
| 1 am |
| -1 |
| 2 am |
| -1.3 |
| 3 am |
| -1.2 |
| 4 am |
| -0.9 |
| 5 am |
| -0.3 |
| 6 am |
| 0.5 |
| 7 am |
| 1.1 |
| 8 am |
| 1.2 |
| 9 am |
| 1.1 |
| 10 am |
| 0.8 |
| 11 am |
| 0.2 |
| 12 pm |
| -0.8 |
| 1 pm |
| -1.6 |
| 2 pm |
| -2.1 |
| 3 pm |
| -2 |
| 4 pm |
| -1.6 |
| 5 pm |
| -1 |
| 6 pm |
| -0.2 |
| 7 pm |
| 0.7 |
| 8 pm |
| 1.1 |
| 9 pm |
| 1.3 |
| 10 pm |
| 1.4 |
| 11 pm |
| 1.1 |
FXUS62 KKEY 151739 AFDKEY
Area Forecast Discussion National Weather Service Key West FL 139 PM EDT Fri May 15 2026
New AVIATION
KEY MESSAGES
- Very warm and humid conditions will continue across the Florida Keys, raising the risk for heat-related illnesses this weekend.
- Rain and thunder chances will remain slim through the first half of the weekend.
- Breezy conditions are possible by early next week.
DISCUSSION
Issued at 1026 AM EDT Fri May 15 2026 The southern stream features a trough-ridge-trough triplet, with the latter upper-level trough axis very near the Keys. The lower and mid-level GOES water vapor channels highlight intense subsidence on the back side of the trough axis, corroborated by the dearth of moisture sampled by the 12Z KKEY RAOB above 830 mb.
Below the inversion, shallow northwesterlies suggest the Keys are post frontal and the dewpoints in the upper 60s are indeed rather rare for mid-May in the Florida Keys. Surface winds and low-level steering should become variable this afternoon suggesting congealing cumulus along the island chain. However, even with modified SFC parcels (92F), the CIN associated with the stout inversion will limit vertical development to 'french toast' thickness, 'biscuits' at best. The forecast calls for nil rain chances and highs near 90. We will be watching RH on the bigger islands with some locations expected to fall into the lower 40s during peak heating, barring any dewpoint crashes.
MARINE
Issued at 1026 AM EDT Fri May 15 2026 Light to gentle breezes will prevail this afternoon through Saturday. High pressure developing over the Southeast will take root across the western North Atlantic over the weekend. As a result, moderate to fresh easterly breezes will peak and lull across the Florida Keys Sunday through Tuesday.
AVIATION
(18Z TAFS)
Issued at 138 PM EDT Fri May 15 2026 VFR and light breezes will prevail at the EYW and MTH terminals through the evening. Initially variable breezes will turn to the esat-southeast overnight.
KEY WATCHES/WARNINGS/ADVISORIES
FL...None.
GM...None.
Area Forecast Discussion National Weather Service Key West FL 139 PM EDT Fri May 15 2026
New AVIATION
KEY MESSAGES
- Very warm and humid conditions will continue across the Florida Keys, raising the risk for heat-related illnesses this weekend.
- Rain and thunder chances will remain slim through the first half of the weekend.
- Breezy conditions are possible by early next week.
DISCUSSION
Issued at 1026 AM EDT Fri May 15 2026 The southern stream features a trough-ridge-trough triplet, with the latter upper-level trough axis very near the Keys. The lower and mid-level GOES water vapor channels highlight intense subsidence on the back side of the trough axis, corroborated by the dearth of moisture sampled by the 12Z KKEY RAOB above 830 mb.
Below the inversion, shallow northwesterlies suggest the Keys are post frontal and the dewpoints in the upper 60s are indeed rather rare for mid-May in the Florida Keys. Surface winds and low-level steering should become variable this afternoon suggesting congealing cumulus along the island chain. However, even with modified SFC parcels (92F), the CIN associated with the stout inversion will limit vertical development to 'french toast' thickness, 'biscuits' at best. The forecast calls for nil rain chances and highs near 90. We will be watching RH on the bigger islands with some locations expected to fall into the lower 40s during peak heating, barring any dewpoint crashes.
MARINE
Issued at 1026 AM EDT Fri May 15 2026 Light to gentle breezes will prevail this afternoon through Saturday. High pressure developing over the Southeast will take root across the western North Atlantic over the weekend. As a result, moderate to fresh easterly breezes will peak and lull across the Florida Keys Sunday through Tuesday.
AVIATION
(18Z TAFS)
Issued at 138 PM EDT Fri May 15 2026 VFR and light breezes will prevail at the EYW and MTH terminals through the evening. Initially variable breezes will turn to the esat-southeast overnight.
KEY WATCHES/WARNINGS/ADVISORIES
FL...None.
GM...None.
| Stations | Dist | Age | Wind | Air | Water | Waves | inHg | DewPt |
| VCAF1 - 8723970 - Vaca Key, FL | 4 mi | 58 min | 0G | 81°F | 87°F | 30.03 | ||
| SMKF1 - Sombrero Key, FL | 8 mi | 48 min | SE 5.1G | 81°F | 30.04 | 73°F | ||
| LONF1 - Long Key, FL | 12 mi | 48 min | SSW 4.1G | 82°F | 30.02 | 69°F | ||
| KYWF1 - 8724580 - Key West, FL | 43 mi | 58 min | NE 2.9G | 81°F | 88°F | 30.05 | ||
| SANF1 - Sand Key, FL | 49 mi | 48 min | NNE 4.1G | 81°F | 30.04 | 69°F |
Wind History for Vaca Key, FL
toggle option: (graph/table)
Link to 1 hour of 5 minute data for KMTH
Terminal Aerodrome Forecast (TAF) for KMTH
Wind History Graph: MTH
(wind in knots)
GEOS Local Image of Southeast
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Key West, FL,
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