We blend the main ingredients of good surf — wave size, period, swell direction, wind, and tide — into a 0–100 score, then map it to a simple colour:

• Green — fun, clean and safe for intermediates.
• Amber — surfable but mixed (wind/tide/consistency may be off).
• Red — poor or unsafe for non-experts.

We apply strict safety gates so conditions that are too large or powerful (for intermediates) are always red-flagged. If a beach’s orientation is unknown, we grade conservatively and note that wind impact is estimated. Tides are pulled from the Stormglass Tides API (separate from the main marine feed).

• Waves & wind: Stormglass marine data (multi-model aggregate).
• Tides: Stormglass Tides API (queried separately for accuracy).
• Spot metadata: beach orientation, tide windows and local notes stored in Go Daisy.

We prefer swell-specific variables (height/period/direction) over “combined wave” to avoid wind-sea distortion.

Hourly time-steps for swell and wind; tides follow the official tide table schedule. We refresh the forecast data several times per day as providers publish updates.

We still grade the hour, but we reduce the weight of wind/direction and show “Beach orientation unknown — wind impact estimated.” You can set the orientation later and the grades will automatically improve in accuracy.

Many breaks only work within a certain tide height band. Big spring ranges amplify rip currents and shorebreak — especially with long-period swells. We include a tide score and additional tide safety flags (e.g., spring + long period).

We use a safety check that forces RED when thresholds are exceeded (e.g., too much long-period power, excessive height, strong onshore winds, severe gusts, tide far outside the workable window). These gates override everything else.

We score each hour separately and highlight the top pick, preferring Green > Amber > Red when scores are close. You’ll also see short reasons (e.g., “Offshore 8 kt”, “Near tide turn”).

• 0–44: Red
• 45–69: Amber
• 70–100: Green

We also provide a graded colour ramp (scarlet → amber → bold green) to show nuance within each band.

We stick to royalty-free libraries like Lucide (MIT), Heroicons (MIT) and SVG Repo (CC0). If we include any CC-BY assets (e.g., Game Icons), we add clear attribution in the app.

• Green/Amber/Red: same wave glyph tinted by score.
• Period: animated phase speed (e.g., “waves every 10 s”).
• Height: relative size element (e.g., buoy mast or stacked crests) to avoid confusion with period.

We use high-contrast colour choices, avoid relying on colour alone (badges + labels), respect prefers-reduced-motion for animations, and provide aria-labels for icons. Text on coloured backgrounds uses white with subtle shadow for legibility.

Anywhere covered by Stormglass. Local accuracy improves when we add spot-specific settings (orientation, tide windows, wind shelter notes).

Minimal. If you opt in, we keep your skill level, unit preferences, and favourite spots to personalise grades. No tracking of precise location without explicit permission.

• Sandbar shifts can make otherwise “green” ingredients underperform.
• Local wind eddies and cliffs can differ from model wind — we adjust when we have crowd-sourced notes.
• Extreme events (storms, rogue sets) aren’t perfectly captured by any model; always use judgement on the day.

Please use the in-app feedback button or email hello@godaisy.app. Screenshots help.

• TODO: Add a per-spot beach orientation list (bearing in degrees) and a quick editor.
• TODO: Define tide profiles per spot (min/max workable height, stage weights, near-turn bonus).
• TODO: Add an Attribution page (if using any CC-BY icons) — include names/links.
• TODO: Expose unit preferences (metres/feet, knots/km h) and persist per user.
• TODO: Implement multi-skill views (Novice / Intermediate / Advanced toggle) affecting safety gates.
• TODO: Add push notifications for “green window starts in X minutes”.
• TODO: Add an accessibility contrast check to the colour ramp (WCAG AA for badges).
• TODO: Optional “local knowledge” notes per spot (e.g., wind shelter, mid-tide banks).

Forecasts are guidance, not guarantees. Ocean conditions can change rapidly. Always follow local advice and surf within your ability.