Map › USA › Florida Keys - Marathon › Grassy Flats Resort
Florida Gulf + Keys · Grassy Key / Middle Keys · Monroe County · Marathon, Florida
Grassy Flats Resort
also known as Grassy Flats Resort & Beach Club, Florida Keys Waterman at Grassy Flats, The Lagoon at Grassy Flats
Nearby Curry Hammock 3 km · Coco Plum Beach 6 km · Anne's Beach 24 km · Veterans Memorial Park (Vets Beach) 29 km · Bahia Honda State Park 33 km · Whale Harbor Marina 40 km · straight-line distance
When it fills in
Frontal and trade wind rather than a daily thermal, so there is no fixed hour. By mid-morning the day has usually declared itself, and lessons are scheduled on that basis.
The wind
locals call it Florida Keys winter north/east wind and frontal/trade pattern
Direction
Kite sizes
metres · typical quiver highlighted
Character
mixed
fills in: Frontal and trade wind rather than a daily thermal, so there is no fixed hour. By mid-morning the day has usually declared itself, and lessons are scheduled on that basis.
Typical strength
15-20 kt in the November-April sweet spot.
Thermal or synoptic
frontal and trade
Also on record
The nearest station is Florida Keys Marathon International Airport: an annual average of E at 8 kt with 20 kt gusts over 2005-2026. That is airport climatology, not a session average on the flat.
The quiver, in words
Men most often ride 12, 14 and 15 m, with a 17 m for light days; women most commonly 10 and 12 m.
Direction to shore
The resort is oceanfront on Grassy Key and the flat opens roughly southeast, along an island line that runs northeast to southwest. So east and northeast come in side-on to side-shore, south and southeast are straight onshore, and the north wind that carries the winter season blows off the land across the flat.Indicative: taken from the resort's oceanfront position and the run of the key, not from a published bearing.
Dominant direction
N and E are the reported directions. Wider lists add NE, S, SW as well; that broader set is unconfirmed.
Forecast
Month by month
- Jan, riders' month91
- Feb, riders' month85
- Mar, riders' month92
- Apr, riders' month90
- May74
- Jun69
- Jul69
- Aug72
- Sep57
- Oct85
- Nov, riders' month82
- Dec, riders' month88
per cent of the month at force 4 or more
Ringed months are the ones riders and schools name: Jan, Feb, Mar, Apr, Nov, Dec.
- 16Jan24°
- 16Feb24°
- 16Mar26°
- 16Apr27°
- 13May30°
- 13Jun31°
- 13Jul32°
- 14Aug32°
- 13Sep31°
- 16Oct29°
- 16Nov27°
- 17Dec25°
avg knots per month · water °C below · season highlighted
| Month | Force 4+ | Knots | From | Air | Water |
|---|---|---|---|---|---|
| Jan | 91% | 16 kt | ESE | 22°C | 23.7°C |
| Feb | 85% | 15.5 kt | E | 22.6°C | 24.1°C |
| Mar | 92% | 16.4 kt | SE | 24.3°C | 26.2°C |
| Apr | 90% | 16.3 kt | E | 24.9°C | 26.7°C |
| May | 74% | 13.3 kt | E | 26.7°C | 29.6°C |
| Jun | 69% | 13.3 kt | E | 27.8°C | 30.6°C |
| Jul | 69% | 12.7 kt | ESE | 29.3°C | 31.9°C |
| Aug | 72% | 13.6 kt | E | 29.2°C | 31.6°C |
| Sep | 57% | 13.2 kt | ESE | 28.8°C | 31.2°C |
| Oct | 85% | 15.6 kt | ENE | 26.7°C | 28.6°C |
| Nov | 82% | 16 kt | E | 25.5°C | 27°C |
| Dec | 88% | 16.9 kt | NE | 22.7°C | 24.6°C |
modelled
A weather model's cell over this place, not a station on it. Good for comparing places, weaker for one beach.
Modelled from weather reanalysis on a 10–25 km grid (2022-2024), not a ground station: reliable for trade and synoptic winds, understates thermal sea breezes and valley winds. The typical daily max and the direction are columns of the table above, month by month. Highlighted months are the riding season from the spot record.
ERA5 reanalysis grid point (modelled) · Open-Meteo historical weather API — ECMWF ERA5/ERA5-Land reanalysis, not a ground station · 2022-2024
The water
Type
flat
Standing depth
Yes in parts. The water out front is shallow enough to stand and walk out of when something goes wrong, and still deep enough to crash into safely as you progress.
Tides
Tide affected Keys flats, but no spot-specific tide window or tide-station rule is published for Grassy Flats.
Temperature
31°C summer · 22°C winter
Wetsuit
Boardshorts year-round through the core season, with a thin 2 or 3 mm shorty or neo top on colder days; a full 3 mm is rarely needed. Winter water sits in the low-70s F, summer in the upper-80s F.
Currents
No current hazard specific to the resort flat is confirmed. Channels open in several directions for foilers, so ask staff about tide and current before you use them.
Your level
The scene
What riders come here for
Launch and rules
three ways on to the water, and what each one asks of you
With a school or a boat
6 schools name this spot
On your own
Room to launch: Resort beachfront with managed grass for rigging. An earlier description of more than 500 ft of beach and grassy packing areas is unconfirmed against the resort's current pages.
Somewhere else
Curry Hammock, 3 km
Every spot within 40 km is on the map at the top of this page, with its distance under it.
Rescue
Launch
Beachfront launch on resort property at 58182 Overseas Highway, Grassy Key. The flat is directly out front, with lessons, open sessions and progression work run from the property. Day passes and beach access for non-overnight guests are sold; check what they actually cover.
Space
Resort beachfront with managed grass for rigging. An earlier description of more than 500 ft of beach and grassy packing areas is unconfirmed against the resort's current pages.
Rules & access
Access rules drift faster than anything else we hold — check locally, and propose an edit if this has changed.
Rider tips
- Settle access before you pack: this is a private resort flat, not a public launch.
- Book the first session through the school, since the channels, the tide and resort operations decide where you can safely ride.
- Pack bigger than you would for a windy destination: 12, 14 and 15 m do most of the work, a 17 m covers the light days, 10 and 12 m for lighter riders.
- Shuffle your feet in the shallows for rays and wear a rashguard; the sun off the flat is relentless.
- When the wind dies, the on-site cable park is a session rather than a lost day.
Getting there
Airport
Key West International Airport (EYW) is the nearest scheduled-service airport for Marathon/Grassy Key; Miami International Airport (MIA) is the main long-haul gateway. Florida Keys Marathon International Airport (MTH) is local but primarily general aviation in current county/travel sources.
Route
Drive US-1/Overseas Highway to 58182 Overseas Highway on Grassy Key, just east of Marathon. From Miami/Fort Lauderdale, Florida Keys tourism routes visitors down the Turnpike to Florida City and then along US-1.
Cost level
high
Staying
On-site resort rooms and suites at Grassy Flats, plus other Marathon/Grassy Key resorts, hotels, marinas and vacation rentals.
No-wind days
On-property cable and wake park, eFoil lessons, sailing, paddling, aquabanas, pools, sauna, biking, restaurants, bars. In Marathon: the Dolphin Research Center, the Turtle Hospital, Aquarium Encounters, Crane Point, Sombrero Beach, fishing.
Photos
FAQ
Is Grassy Flats Resort good for beginners?
Yes, the resort runs a staged progression from cable-board and kite-handling skills to open-water riding, with staff coaching for beginners through advanced foilers.
What is the wind like at Grassy Flats Resort?
The resort describes clean, consistent 15-20 knot north and east wind in its November-through-April prime season, with December and February-April as the strongest stretch.
Are there rules or access fees at Grassy Flats Resort?
As of 2026 it is a private resort rather than a public beach, with day-pass access from $55 and watersports subject to closure in unsafe weather.
What are the hazards at Grassy Flats Resort?
The bottom is mostly sea grass with occasional shells and rays in the shallows, and access depends on resort guest status or a purchased day pass.
Last updated: August 2026