How the AURA Score Works

Sardinians know how to pick the right beach instinctively. They read the wind from the kitchen window, watch where the clouds come from, and they know that if the Mistral is blowing it's pointless to drive to Is Arutas, while Sciroccо calls for Stintino. Visitors, especially first-timers, have none of that intuition. AURA was built to give anyone the same local instinct, grounded in measurable, hour-by-hour data.

The score boils down to a single 0–10 number five factors that shape a real day at the beach: wind, waves, coastline exposure, weather and Posidonia / seagrass risk. You'll find it on every beach page, in the today's ranking, and on every themed listing.

Wind is what separates a memorable day from a day you'll abandon by eleven. AURA evaluates two things: the speed in km/h and — more importantly — the direction the wind is coming from relative to the orientation of the shore.

A 25 km/h gust blowing off the land (offshore) leaves the sea glassy and the umbrella standing. The same gust coming in off the open sea (onshore) lifts sand, ruffles the water and makes reading impossible. We know the exact coastline orientation for every beach and compute whether the forecast winds are blowing offshore (positive), alongshore (neutral) or onshore (penalising).

Wind data comes from two cross-referenced sources: the high-resolution Open-Meteo model and — when available — real physical stations from the ARPAS Sardegna network, the regional weather agency. We always prefer the closest observed reading over a forecast: a forecast can be wrong, an actual measurement can't.

For wave action we use Open-Meteo Marine, which provides significant wave height, period and direction. Under 30 cm we treat the sea as flat; 30 to 80 cm is workable on most beaches; above one metre the score drops fast — surf, shorebreak, difficult conditions for children, and possibly dangerous on rocky shores. Exposure matters here too: the one-metre swell that wrecks a li-lo at Maria Pia is invisible inside the bay of Porto Istana.

Every beach has an exposure profile mapping, for each of the eight major winds (Mistral, Tramontana, Grecale, Levante, Sirocco, Ostro, Libeccio, Ponente), whether the bay is sheltered, partially sheltered or exposed. That mapping isn't an automated guess: it's been verified by hand for each beach, combining coastline orientation, the presence of headlands and ridges, and documented local knowledge. It's why pages like best beaches when the Mistral blows make sense even on the worst-wind days.

Posidonia oceanica is a protected sea plant that grows on healthy Sardinian seabeds: its presence is an excellent biological sign, but dead leaves wash ashore when the sea pushes them inside the bay. It's not litter, it's a natural phenomenon — but for many visitors it's a deciding factor. AURA computes a daily Posidonia risk index for beaches known to accumulate it, based on recent wave direction and swell.

When the risk is high we say so on the beach page. It isn't a verdict against the beach: it just means today, on that specific beach, you're likely to find leaves on the sand. Beaches without habitual accumulation are flagged separately.

Sun, cloud cover, rain probability and felt temperature enter the calculation with a smaller weight than wind, but they're the final modifier. A clear day at 28°C with calm sea is a solid 10; the same beach with overcast skies at 19°C drops to a 7. Below 18°C or with meaningful rain, the score caps at 6 even with perfect wind.

• Green (8–10): a fully enjoyable day. Calm or near-calm sea, light or offshore wind, good weather. This is the score you want when you only have one free day.
• Amber (5–7): workable with small compromises. Maybe some afternoon wind, maybe a moderate swell, maybe clouds. An amber beach is often still a great pick if you know its weak points and get there early.
• Red (0–4): we'd advise against it for a relaxed day. Sustained onshore wind, high surf, or bad weather. A beach that's red today is usually green tomorrow — the score is about a specific day, not the beach itself.

Three practical reasons. First: observed data, not just forecasts — when an ARPAS station is in range, AURA always prefers the real reading. Second: hand-verified exposure — the wind-by-wind shelter map for each beach is an audit, not an algorithm. Third: hourly refresh — the forecast updates continuously and the score is recomputed, so what you see at 8am reflects the latest available data.