5 Ways to Use Marine Weather Data in Your App

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Marine weather data has obvious applications — but once you start building with it, you realize how many different types of apps and features it can power. Whether you're building a consumer app, an internal tool for a marina, or adding weather context to an existing product, the SeaLegs API gives you the building blocks.

Here are five practical ways developers are using marine weather data today, with code examples you can adapt for your own projects.

1. Real-Time Conditions Dashboard

The most straightforward use case: show your users what conditions look like right now (and over the next few days) at a specific location. Marinas, charter businesses, yacht clubs, and coastal tourism sites all benefit from having live marine conditions on their website or app.

The fastest way to do this is with a SpotCast widget — no backend code required. But if you want full control over the design, you can call the API directly:

curl -X POST https://api.sealegs.ai/v3/spotcast \
  -H "X-API-Key: your_api_key" \
  -d '{
    "latitude": 26.101,
    "longitude": -80.108,
    "start_date": "2026-01-15",
    "num_days": 3
  }'

The response includes an AI-generated summary of conditions plus daily classifications (GO, CAUTION, or AVOID) that you can map to colors in your UI. No need to interpret raw weather models yourself — the API does the analysis for you.

2. Smart Trip Planning

If your app helps people plan trips on the water, you can use the SpotCast API to give them an AI-powered recommendation for whether their planned outing is a go or not.

The key is the trip_duration_hours and vessel_info parameters. These let the AI tailor its analysis to your user's specific situation:

curl -X POST https://api.sealegs.ai/v3/spotcast \
  -H "X-API-Key: your_api_key" \
  -d '{
    "latitude": 25.954,
    "longitude": -79.743,
    "start_date": "2026-01-20",
    "num_days": 3,
    "trip_duration_hours": 6,
    "vessel_info": {
      "type": "sailboat",
      "length_ft": 35
    }
  }'

A 35-foot sailboat has very different comfort and safety thresholds than a personal watercraft. The API adjusts its GO/CAUTION/AVOID classifications and the written summary accordingly. So if conditions are fine for a yacht but risky for a kayak, your users get the right recommendation for their vessel.

You can build this into a trip booking flow: before a customer confirms a charter, show them the forecast. If it's CAUTION, suggest alternative dates. If it's GO, give them confidence their trip will be great.

3. Automated Weather Alerts

Instead of making your users check a dashboard, bring the weather to them. The SeaLegs webhook system sends a POST request to your server as soon as a forecast is ready — you can use this to trigger push notifications, emails, or Slack messages.

Here's how it works: when you create a SpotCast, include a webhook_url:

curl -X POST https://api.sealegs.ai/v3/spotcast \
  -H "X-API-Key: your_api_key" \
  -d '{
    "latitude": 40.461,
    "longitude": -73.577,
    "start_date": "2026-01-15",
    "num_days": 1,
    "webhook_url": "https://yourapp.com/api/weather-webhook",
    "metadata": {
      "user_id": "usr_123",
      "location_name": "Hudson Canyon"
    }
  }'

When the forecast completes, SeaLegs sends a POST to your endpoint with the summary, classification, and your custom metadata. You can then parse the result and decide what to do — send an alert if conditions are dangerous, or a "great day to go out" notification if it's GO.

For a daily alerting system, set up a cron job that creates SpotCasts for all your users' saved locations each morning. The webhooks fire when each forecast is ready, and your backend routes the alerts to the right people.

4. Activity-Specific Forecasts

Not all water activities have the same weather requirements. A kite surfer wants wind; a kayaker doesn't. A deep-sea fishing charter cares about swell period; a harbor cruise cares about wave height.

The vessel_info parameter adjusts the AI analysis to different activity types:

• "type": "powerBoat" — standard recreational boating thresholds
• "type": "sailboat" — factors in wind more favorably, adjusts wave tolerance
• "type": "pwc" — personal watercraft (jet ski), tighter thresholds for wave height
• "type": "yacht" — larger vessel, more tolerant of rough conditions
• "type": "catamaran" — stability-focused analysis

Combined with length_ft, this gives the AI enough context to generate meaningfully different recommendations. A 20-foot center console and a 50-foot sportfisher will get different verdicts for the same conditions.

If you're building an app for a specific niche — fishing, sailing, diving, paddleboarding — this means you can offer forecasts that actually make sense for your users' activity, not generic marine weather that they have to interpret themselves.

5. Multi-Location Comparison

Sometimes the question isn't "what will the weather be?" but "where should I go?" If your app covers multiple locations — a network of marinas, a list of fishing spots, or regional surfing conditions — you can create SpotCasts for multiple coordinates and compare the results.

# Request forecasts for three locations
for location in [
    {"lat": 25.954, "lon": -79.743, "name": "Bimini"},
    {"lat": 24.555, "lon": -81.782, "name": "Key West"},
    {"lat": 26.101, "lon": -80.108, "name": "Fort Lauderdale"}
]:
    response = requests.post(
        "https://api.sealegs.ai/v3/spotcast",
        headers={"X-API-Key": api_key},
        json={
            "latitude": location["lat"],
            "longitude": location["lon"],
            "start_date": "2026-01-20",
            "num_days": 3,
            "metadata": {"location_name": location["name"]}
        }
    )

Once all the forecasts come back, you can rank locations by classification and show your users which spots have the best conditions. "Key West is GO for the next 3 days, Bimini is CAUTION on Saturday" is a lot more useful than a wall of wind speeds and wave heights. See our Florida coverage page for more coordinates across the region.

This pattern works especially well for:

• Fishing apps — compare conditions at offshore spots like the Gulf of Mexico and suggest the best one
• Charter platforms — show customers which departure ports have the best weather window
• Regional marine weather sites — display a map of conditions across an area
• Sailing race committees — evaluate conditions at multiple course areas

Multi-Language Support

One more thing worth mentioning: all of these use cases work in six languages. If your app serves an international audience, pass the language preference and the AI-generated summaries come back localized:

"preferences": {
  "language": "es",
  "distance_units": "km",
  "speed_units": "kts"
}

Supported languages: English, Spanish, French, Portuguese, Italian, and Japanese.

Getting Started

All five of these patterns use the same SpotCast endpoint. The difference is in how you structure the request and what you do with the response. Start with a single location dashboard, and as your product matures you can layer in trip planning, alerts, and multi-location features.

Check out the Quickstart Guide to make your first API call, or create a free developer account to start building.