Sydney Dive Conditions

Every dive site handles weather differently: a howling southerly that closes Shark Point can mean a perfect morning at Kurnell or Clifton Gardens. This page pulls the live marine forecast and rates each site for the conditions it actually feels.

Coverage now spans the whole NSW coast, 287 sites from Byron Bay to Eden across 16 coastal areas, following Michael McFadyen's full NSW guides plus operator, club and park documented sites his guides never covered (each flagged in its description). The area picker in the toolbar starts on Sydney; choose another area or "All NSW" and the list, map, best-day markers, tides and water temperature all follow. Your choice is remembered on this device.

How the score works

• Sea state (45%): both swell trains plus wind waves, combined by wave energy (height² × period) and scaled by each site's directional exposure and depth. A long groundswell hits far harder than chop of the same height; surge reaches roughly period²/4 metres, so a deep wreck ignores what closes a shallow reef, and long-period swell wraps around headlands into "protected" sites.
• Wind (20%): onshore wind over ~10 kn kills exposed shore entries; boats want under 15 kn unless it's W/NW (which flattens the sea inshore); steep wind-chop stops boat runs regardless of the score.
• Visibility estimate (35%): each site's typical vis with a seasonal factor (winter is statistically far clearer than Oct–Nov), reduced by recent sea state and by rain beyond each water body's tolerance. The open ocean shrugs off most rain; Port Hacking doesn't. Sustained southerlies get a small upwelling bonus.

Each day's rating is the best 3-hour daylight window, so a morning glass-off still counts.

Scores: 7–10 Good · 5–7 Fair · 3–5 Poor · 0–3 No-go/Blown out. Thresholds and seasonal factors are calibrated against Michael McFadyen's published Sydney statistics (1,700+ logged dives) and his weather-and-diving guides.

Data sources

• Marine forecast (two swell partitions, wind waves, ocean currents, sea temperature, modelled sea level): Open-Meteo Marine API (CC-BY 4.0)
• Weather forecast (wind, rainfall, air temperature, cloud): Open-Meteo Forecast API (CC-BY 4.0)
• River discharge for flood-runoff detection (Parramatta, Georges, Hacking, Hawkesbury): Open-Meteo Flood API / GloFAS (CC-BY 4.0)
• Daily pollution forecasts & water-quality grades: NSW Beachwatch (© State of NSW; fetched via a public CORS proxy since the API doesn't allow direct browser access. Display only: it never affects the score)
• Basemaps: Esri World Imagery; © OpenStreetMap contributors © CARTO
• Site knowledge inspired by decades of Sydney dive lore, especially Michael McFadyen's dive site guides. Go there for proper site briefings.

Please read this bit

These ratings are automated estimates from offshore weather models. They know nothing about today's actual water, and visibility is a modelled guess, not a report. Conditions on the rock platform beat any forecast: always assess in person, dive within your training, and if in doubt, don't go out. Tide-critical sites (Shiprock, the Kurnell drift dives) must be planned against official tide tables.