SeaLegs AI Marine Forecast API

Get AI-powered marine weather forecasts for any location worldwide

Install

openclaw skills install @sealegs-ai-coder/sealegs-marine-forecast

SeaLegs AI Marine Forecast API

Get AI-powered marine weather forecasts for any location worldwide. Includes wind, waves, visibility, precipitation analysis with GO/CAUTION/NO-GO safety classifications.

Features

SpotCast Forecasts: Get marine weather forecasts for any coordinates worldwide
AI Safety Analysis: GO / CAUTION / NO-GO classifications for each day
Vessel-Specific: Tailored recommendations based on boat type and size
Multi-Language: Supports English, Spanish, French, Portuguese, Italian, Japanese

Setup

1. Get an API Key

Sign up at https://developer.sealegs.ai — you'll get 10 free credits to get started
Generate an API key from your dashboard
Need more? Add credits anytime ($10 = 200 forecast-days)

2. Configure OpenClaw

Add to your OpenClaw configuration:

json5

{
  skills: {
    entries: {
      "sealegs-marine-forecast": {
        enabled: true,
        apiKey: "sk_live_your_key_here"
      }
    }
  }
}

Or set the environment variable:

bash

export SEALEGS_API_KEY=sk_live_your_key_here

3. Install the Skill

bash

clawhub install sealegs-marine-forecast

Usage Example

jsonc

// Miami, FL
POST /v3/spotcast
{
  "latitude": 25.7617,
  "longitude": -80.1918,
  "start_date": "2026-02-10T00:00:00Z",
  "num_days": 2,
  "vessel_info": {"type": "sailboat", "length_ft": 35}  // optional
}

Sample response:

json

{
  "id": "spc_FrZdSAs6T3cxbXiPtNZvxu",
  "coordinates": {
    "latitude": 25.7617,
    "longitude": -80.1918
  },
  "forecast_period": {
    "start_date": "2026-02-10T00:00:00-05:00",
    "end_date": "2026-02-11T23:59:59-05:00",
    "num_days": "2"
  },
  "trip_duration_hours": "12",
  "metadata": {
    "location_name": "Miami Marina"
  },
  "latest_forecast": {
    "status": "completed",
    "ai_analysis": {
      "summary": "Ideal conditions both days with light winds",
      "daily_classifications": [
        {
          "date": "2026-02-10",
          "classification": "GO",
          "short_summary": "Outstanding conditions all day with light winds under 7kt and calm 1.1-1.6ft seas. Best window is morning 5:00 AM-12:00 PM with nearly calm 1-4kt northwest winds and comfortable 1.4ft seas at 11-second periods.",
          "summary": "Outstanding sailing conditions throughout Monday with exceptionally light winds and calm seas. Morning hours offer the best window with nearly calm 1-4kt northwest winds and comfortable 1.4ft seas at 11-second periods from the northeast."
        },
        {
          "date": "2026-02-11",
          "classification": "GO",
          "short_summary": "Exceptional conditions with very light winds 1-6kt and minimal 1.2-1.3ft seas all day. Best window 9:00 AM-1:00 PM offers glassy conditions with 1-3kt winds and 1.2ft seas at 11-second periods.",
          "summary": "Exceptional boating conditions on Tuesday with very light winds and minimal seas throughout the day. Morning through midday provides ideal glassy conditions with 1-3kt east-southeast winds and 1.2ft seas at 10-11 second periods from the northeast."
        }
      ]
    }
  }
}

API Endpoints

Operation	Endpoint	Cost
Create forecast	POST /v3/spotcast	1 credit/day
Get forecast	GET /v3/spotcast/{id}	Free
Check status	GET /v3/spotcast/{id}/status	Free
Refresh forecast	POST /v3/spotcast/{id}/refresh	1 credit/day
List forecasts for SpotCast	GET /v3/spotcast/{id}/forecasts	Free
Get specific forecast	GET /v3/spotcast/{id}/forecast/{forecast_id}	Free
List SpotCasts	GET /v3/spotcasts	Free
Get balance	GET /v3/account/balance	Free

Weather Factors Used

Wind speed, gusts, and direction
Wave height, period, and direction
Visibility and fog probability
Precipitation probability and intensity
Air and water temperature

Authentication

All requests require:

text

Authorization: Bearer $SEALEGS_API_KEY
Content-Type: application/json

Rate Limits

Standard tier: 60 requests per minute
Rate limit headers included in all responses: X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset

Billing

1 credit per forecast-day (3-day forecast = 3 credits)
GET operations are free
Refreshes cost 1 credit per forecast-day

SpotCast Forecasts

SpotCast generates AI-powered marine weather forecasts for specific coordinates.

Create SpotCast

POST https://api.sealegs.ai/v3/spotcast

Creates a new forecast request. Processing is asynchronous (typically 30-60 seconds).

Required parameters:

latitude (number): -90 to 90
longitude (number): -180 to 180
start_date (string): ISO 8601 format (e.g., "2025-12-05T00:00:00Z")
num_days (integer): 1-5

Optional parameters:

webhook_url (string): HTTPS endpoint for completion notification
metadata (object): Custom key-value pairs for your reference
trip_duration_hours (integer): Trip duration in hours
preferences.language: en, es, fr, pt, it, ja (default: en)
preferences.distance_units: nm, mi, km (default: nm)
preferences.speed_units: kts, mph, ms (default: kts)
vessel_info.type: powerBoat, sailboat, pwc, yacht, catamaran
vessel_info.length_ft: 1-500

Example request:

bash

curl -X POST https://api.sealegs.ai/v3/spotcast \
  -H "Authorization: Bearer $SEALEGS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "latitude": 25.7617,
    "longitude": -80.1918,
    "start_date": "2025-12-05T00:00:00Z",
    "num_days": 2,
    "vessel_info": {"type": "sailboat", "length_ft": 35}
  }'

Response (202 Accepted):

json

{
  "id": "spc_abc123xyz",
  "forecast_id": "fcst_xyz789",
  "status": "processing",
  "created_at": "2025-12-01T10:30:00Z",
  "estimated_completion_seconds": 45,
  "credits_charged": 2,
  "credits_remaining": 98,
  "links": {
    "self": "https://api.sealegs.ai/v3/spotcast/spc_abc123xyz",
    "forecast": "https://api.sealegs.ai/v3/spotcast/spc_abc123xyz/forecast/fcst_xyz789",
    "status": "https://api.sealegs.ai/v3/spotcast/spc_abc123xyz/status"
  }
}

Check SpotCast Status

GET https://api.sealegs.ai/v3/spotcast/{id}/status

Poll this endpoint until status is "completed" or "failed". Recommended poll interval: 10-15 seconds.

Status values:

pending: Queued for processing (no progress field)
processing: Currently generating forecast (includes progress)
completed: Ready to retrieve (includes progress at 100%)
failed: Error occurred

Progress stages (only present when status is processing or completed):

fetching_weather
processing_data
ai_analysis
completing
completed (100%)

Example request:

bash

curl https://api.sealegs.ai/v3/spotcast/spc_abc123xyz/status \
  -H "Authorization: Bearer $SEALEGS_API_KEY"

Response (pending):

json

{
  "id": "spc_abc123xyz",
  "forecast_id": "fcst_xyz789",
  "status": "pending",
  "created_at": "2025-12-01T10:30:00Z"
}

Response (processing):

json

{
  "id": "spc_abc123xyz",
  "forecast_id": "fcst_xyz789",
  "status": "processing",
  "created_at": "2025-12-01T10:30:00Z",
  "progress": {
    "stage": "ai_analysis",
    "percentage": 75
  }
}

Response (completed):

json

{
  "id": "spc_abc123xyz",
  "forecast_id": "fcst_xyz789",
  "status": "completed",
  "created_at": "2025-12-01T10:30:00Z",
  "completed_at": "2025-12-01T10:30:45Z",
  "progress": {
    "stage": "completed",
    "percentage": 100
  }
}

Get SpotCast

GET https://api.sealegs.ai/v3/spotcast/{id}

Retrieves the completed forecast with AI analysis.

Example request:

bash

curl https://api.sealegs.ai/v3/spotcast/spc_abc123xyz \
  -H "Authorization: Bearer $SEALEGS_API_KEY"

Response (200 OK):

json

{
  "id": "spc_abc123xyz",
  "created_at": "2025-12-01T10:30:00Z",
  "coordinates": {
    "latitude": 25.7617,
    "longitude": -80.1918
  },
  "forecast_period": {
    "start_date": "2025-12-05T00:00:00Z",
    "end_date": "2025-12-06T00:00:00Z",
    "num_days": 2
  },
  "trip_duration_hours": 12,
  "forecast_count": 1,
  "metadata": {
    "location_name": "Miami Marina"
  },
  "latest_forecast": {
    "forecast_id": "fcst_xyz789",
    "status": "completed",
    "created_at": "2025-12-01T10:30:00Z",
    "completed_at": "2025-12-01T10:30:45Z",
    "ai_analysis": {
      "summary": "Excellent conditions expected. Light winds 8-12kt from the NE with calm 1-2ft seas.",
      "daily_classifications": [
        {
          "date": "2025-12-05",
          "classification": "GO",
          "summary": "Light winds 8-12kt from NE. Seas 1-2ft. Visibility excellent at 10+ nm. No precipitation expected."
        },
        {
          "date": "2025-12-06",
          "classification": "CAUTION",
          "summary": "Winds increasing to 15-20kt. Seas building to 3-4ft by afternoon. Morning departure recommended."
        }
      ]
    }
  }
}

Refresh SpotCast

POST https://api.sealegs.ai/v3/spotcast/{id}/refresh

Updates an existing forecast with the latest weather data. Costs 1 credit per forecast-day.

Optional body:

webhook_url (string): Override webhook for this refresh

Example request:

bash

curl -X POST https://api.sealegs.ai/v3/spotcast/spc_abc123xyz/refresh \
  -H "Authorization: Bearer $SEALEGS_API_KEY"

Response (202 Accepted):

json

{
  "id": "spc_abc123xyz",
  "forecast_id": "fcst_newxyz789",
  "status": "processing",
  "created_at": "2025-12-02T08:00:00Z",
  "links": {
    "self": "https://api.sealegs.ai/v3/spotcast/spc_abc123xyz",
    "status": "https://api.sealegs.ai/v3/spotcast/spc_abc123xyz/status"
  }
}

List Forecasts

GET https://api.sealegs.ai/v3/spotcast/{id}/forecasts

Lists all forecasts for a SpotCast, sorted by creation date (newest first). Each time you create or refresh a SpotCast, a new forecast is generated.

Query parameters:

limit (integer): Number of results to return (default: 10)

Example request:

bash

curl "https://api.sealegs.ai/v3/spotcast/spc_abc123xyz/forecasts?limit=5" \
  -H "Authorization: Bearer $SEALEGS_API_KEY"

Response (200 OK):

json

{
  "spotcast_id": "spc_abc123xyz",
  "data": [
    {
      "forecast_id": "fcst_newxyz789",
      "status": "completed",
      "created_at": "2025-12-02T08:00:00Z",
      "completed_at": "2025-12-02T08:00:42Z"
    },
    {
      "forecast_id": "fcst_xyz789",
      "status": "completed",
      "created_at": "2025-12-01T10:30:00Z",
      "completed_at": "2025-12-01T10:30:45Z"
    }
  ],
  "has_more": false
}

Get Forecast

GET https://api.sealegs.ai/v3/spotcast/{id}/forecast/{forecast_id}

Retrieves a specific forecast with full details including AI analysis. Use this to access any forecast in a SpotCast's history, not just the latest one.

Example request:

bash

curl "https://api.sealegs.ai/v3/spotcast/spc_abc123xyz/forecast/fcst_xyz789" \
  -H "Authorization: Bearer $SEALEGS_API_KEY"

Response (200 OK - Completed):

json

{
  "forecast_id": "fcst_xyz789",
  "spotcast_id": "spc_abc123xyz",
  "status": "completed",
  "created_at": "2025-12-01T10:30:00Z",
  "completed_at": "2025-12-01T10:30:45Z",
  "forecast_period": {
    "start_date": "2025-12-05T00:00:00Z",
    "num_days": 2
  },
  "ai_analysis": {
    "summary": "Excellent conditions expected. Light winds 8-12kt from the NE with calm 1-2ft seas.",
    "daily_classifications": [
      {
        "date": "2025-12-05",
        "classification": "GO",
        "summary": "Light winds and calm seas throughout the day."
      },
      {
        "date": "2025-12-06",
        "classification": "CAUTION",
        "summary": "Improving conditions with best windows in the afternoon."
      }
    ]
  }
}

Response (200 OK - Processing):

json

{
  "forecast_id": "fcst_xyz789",
  "spotcast_id": "spc_abc123xyz",
  "status": "processing",
  "created_at": "2025-12-01T10:30:00Z",
  "forecast_period": {
    "start_date": "2025-12-05T00:00:00Z",
    "num_days": 2
  },
  "progress": {
    "stage": "analyzing",
    "percentage": 65
  }
}

Response (200 OK - Failed):

json

{
  "forecast_id": "fcst_xyz789",
  "spotcast_id": "spc_abc123xyz",
  "status": "failed",
  "created_at": "2025-12-01T10:30:00Z",
  "forecast_period": {
    "start_date": "2025-12-05T00:00:00Z",
    "num_days": 2
  },
  "error": "Processing failed"
}

List SpotCasts

GET https://api.sealegs.ai/v3/spotcasts

Retrieves all SpotCasts for your account.

Query parameters:

limit (integer): 1-100 results (default: 20)
after (string): Cursor for pagination

Example request:

bash

curl "https://api.sealegs.ai/v3/spotcasts?limit=10" \
  -H "Authorization: Bearer $SEALEGS_API_KEY"

Response (200 OK):

json

{
  "data": [
    {
      "id": "spc_abc123xyz",
      "created_at": "2025-12-01T10:30:00Z",
      "coordinates": {
        "latitude": 25.7617,
        "longitude": -80.1918
      },
      "start_date": "2025-12-05T00:00:00-05:00",
      "end_date": "2025-12-06T23:59:59-05:00",
      "num_days": 2,
      "latest_forecast": {
        "forecast_id": "fcst_xyz789",
        "status": "completed"
      }
    }
  ],
  "has_more": true,
  "next_cursor": "spc_def456"
}

Account

Get Balance

GET https://api.sealegs.ai/v3/account/balance

Returns your current credit balance and usage.

Example request:

bash

curl https://api.sealegs.ai/v3/account/balance \
  -H "Authorization: Bearer $SEALEGS_API_KEY"

Response (200 OK):

json

{
  "credit_balance": 100,
  "total_credits_purchased": 200,
  "total_credits_used": 100,
  "purchase_url": "https://developers.sealegs.ai/dashboard/billing"
}

Webhooks

When you provide a webhook_url during SpotCast creation or refresh, SeaLegs sends a POST request to that URL when processing completes or fails.

Webhook Headers

text

Content-Type: application/json
X-SeaLegs-Event: spotcast.forecast.completed
X-SeaLegs-Signature: sha256=abc123...
X-SeaLegs-Delivery-ID: whk_abc123xyz
X-SeaLegs-Timestamp: 1733045400
User-Agent: SeaLegs-Webhooks/1.0

Verifying Signatures

Every webhook includes an HMAC-SHA256 signature in the X-SeaLegs-Signature header. Your webhook secret is available in the Developer Dashboard. Always verify the signature before processing the payload.

Python:

python

import hmac
import hashlib

def verify_webhook(payload: bytes, signature: str, secret: str) -> bool:
    expected = hmac.new(secret.encode(), payload, hashlib.sha256).hexdigest()
    return hmac.compare_digest(f"sha256={expected}", signature)

JavaScript:

javascript

const crypto = require('crypto');

function verifyWebhook(payload, signature, secret) {
  const expected = crypto.createHmac('sha256', secret).update(payload).digest('hex');
  return crypto.timingSafeEqual(
    Buffer.from(`sha256=${expected}`),
    Buffer.from(signature)
  );
}

Completed Event

json

{
  "event": "spotcast.forecast.completed",
  "created_at": "2025-12-01T10:30:45Z",
  "data": {
    "spotcast_id": "spc_abc123xyz",
    "forecast_id": "fcst_xyz789",
    "status": "completed",
    "summary": "Excellent conditions expected. Light winds 8-12kt from the NE with calm 1-2ft seas.",
    "metadata": {
      "trip_name": "Weekend Fishing Trip"
    }
  }
}

The summary field is included when AI analysis completes successfully. The metadata object is included when you provided metadata in the original POST /v3/spotcast request, echoed back exactly as sent.

Failed Event

json

{
  "event": "spotcast.forecast.failed",
  "created_at": "2025-12-01T10:31:00Z",
  "data": {
    "spotcast_id": "spc_abc123xyz",
    "forecast_id": "fcst_xyz789",
    "status": "failed",
    "error": {
      "code": "processing_failed",
      "message": "Unable to fetch weather data for the specified location"
    },
    "metadata": {
      "trip_name": "Weekend Fishing Trip"
    }
  }
}

Retry Policy

Failed deliveries are retried up to 4 times: after 5 minutes, 30 minutes, 2 hours, and 24 hours.

Understanding Results

Daily Classifications

Each forecast day receives a safety classification:

Classification	Meaning
GO	Safe conditions for the vessel type
CAUTION	Proceed with awareness; conditions may be challenging
NO-GO	Conditions not recommended for the vessel type

Classifications are adjusted based on vessel type and size when vessel_info is provided.

Weather Variables Analyzed

Wind: Speed (kts), gusts, direction (degrees)
Waves: Height (ft), period (seconds), direction, swell
Visibility: Distance (nm), fog probability
Precipitation: Probability (%), intensity
Temperature: Air and water (F/C)

Vessel-Specific Adjustments

When vessel_info is provided:

PWC/Jet Ski: Stricter wave height limits
Sailboats: Wind optimization recommendations
Large Yachts: Higher tolerance for wave conditions
Small Powerboats: Balanced wind/wave thresholds

Error Handling

Error Response Format

json

{
  "error": {
    "code": "invalid_coordinates",
    "message": "Latitude must be between -90 and 90",
    "param": "latitude"
  }
}

HTTP Status Codes

Code	Meaning	Action
200	Success	Request completed
201	Created	Resource created
202	Accepted	Async processing started
400	Bad Request	Check parameter values
401	Unauthorized	Verify API key is correct
402	Payment Required	Add credits at developer.sealegs.ai
403	Forbidden	Account not verified or suspended
404	Not Found	Check resource ID
429	Rate Limited	Wait and retry (60 req/min limit)
500	Server Error	Retry after brief delay

Error Codes

Authentication (401)

Code	Description
`missing_api_key`	No API key provided in request
`invalid_api_key`	API key is not recognized
`key_revoked`	API key has been revoked

Authorization (403)

Code	Description
`account_not_verified`	Developer account has not been verified
`account_suspended`	Developer account has been suspended

Payment (402)

Code	Description
`insufficient_balance`	Not enough credits (response includes `current_balance`, `required_credits`, `purchase_url`)

Validation (400)

Code	Description
`invalid_coordinates`	Coordinates out of valid range
`invalid_date_format`	Not ISO 8601 format
`invalid_webhook_url`	Not a valid HTTPS URL
`invalid_preferences`	Preferences format is invalid
`invalid_language`	Language not supported (use: en, es, fr, pt, it, ja)
`invalid_distance_units`	Distance units not supported (use: nm, mi, km)
`invalid_speed_units`	Speed units not supported (use: kts, mph, ms)
`invalid_json`	Request body is not valid JSON

Not Found (404)

Code	Description
`spotcast_not_found`	The specified SpotCast does not exist
`forecast_not_found`	The specified forecast does not exist

Rate Limit (429)

Code	Description
`rate_limit_exceeded`	Too many requests (response includes `retry_after` seconds)

Server (500)

Code	Description
`internal_error`	An unexpected error occurred
`creation_failed`	Failed to create SpotCast
`retrieval_failed`	Failed to retrieve resource

Common Workflows

Get a Marine Forecast

Create a SpotCast with coordinates and dates
Poll the status endpoint until "completed"
Retrieve the full forecast with AI analysis
Present GO/CAUTION/NO-GO classification to user

Check Conditions Before a Trip

Create SpotCast with trip coordinates and date
Include vessel_info for tailored recommendations
Check daily_classifications for each day
Review AI summary for specific concerns

License

MIT

SeaLegs AI Marine Forecast API

Install

SeaLegs AI Marine Forecast API

Features

Setup

1. Get an API Key

2. Configure OpenClaw

3. Install the Skill

Usage Example

API Endpoints

Weather Factors Used

Authentication

Rate Limits

Billing

SpotCast Forecasts

Create SpotCast

Check SpotCast Status

Get SpotCast

Refresh SpotCast

List Forecasts

Get Forecast

List SpotCasts

Account

Get Balance

Webhooks

Webhook Headers

Verifying Signatures

Completed Event

Failed Event

Retry Policy

Understanding Results

Daily Classifications

Weather Variables Analyzed

Vessel-Specific Adjustments

Error Handling

Error Response Format

HTTP Status Codes

Error Codes

Authentication (401)

Authorization (403)

Payment (402)

Validation (400)

Not Found (404)

Rate Limit (429)

Server (500)

Common Workflows

Get a Marine Forecast

Check Conditions Before a Trip

Links

License

Related skills