This page
White dashed = real observations (BOM stations for temp/wind/rain, MHL wave buoy for swell). Blue = Open-Meteo model (recent past + forecast).
MHL wave buoy: Sydney.
Tide labels are turning points of the Open-Meteo marine model's sea level height, interpolated from its hourly values — heights are relative to mean sea level, not a chart datum, so they're indicative rather than a substitute for an official tide table.
Directional wave spectrum: NSW Manly Hydraulics Laboratory, SYDDOW buoy, cached Mon 12 Oct 14:23 AEDT (reissued hourly). See mhl.nsw.gov.au/Station-SYDDOW.
Synoptic chart: BOM national mean sea-level pressure analysis, cached Mon 12 Oct 14:23 AEDT (reissued roughly every 6h).
Wave period chart: BOM AUSWAVE national peak wave period analysis, cached Mon 12 Oct 14:23 AEDT.
© Commonwealth of Australia, Bureau of Meteorology, see bom.gov.au/copyright.

Forecast & model data — Open-Meteo
Temperature, wind, rain and sunrise/sunset come from Open-Meteo's Forecast API. Tide height (sea_level_height_msl — an approximation referenced to mean sea level rather than a chart datum like LAT) and swell height/period/direction come from its separate Marine API, an ~8km-resolution model. Both include a day of recent-past model analysis alongside the 3-day forecast, so the "past" portion of each panel is a decent stand-in for actual recent conditions.

Real observations — Bureau of Meteorology
Dashed white lines/arrows show real station readings (temperature, wind, rain) from each location's nearest BOM automatic weather station, over the last ~3 days — not always the literal closest station, sometimes picked for reporting reliability instead (e.g. Maroubra uses Sydney Airport over the closer but intermittently-reporting Kurnell). Rain is derived from BOM's rain_trace field (cumulative since 9am local, resetting daily) by differencing consecutive ~30min readings. This is shown alongside the model because Open-Meteo's past-day analysis, while corrected against real observations, still measurably diverges from them — overnight wind speed at an exposed headland, for instance, can be modelled 2-3x too high.

Real wave buoy data — NSW Manly Hydraulics Laboratory
For NSW locations near one of MHL's 7 offshore directional wave buoys, real swell height/period/direction observations (~7-day rolling window) and MHL's own hourly directional wave spectrum plot are shown too. MHL only covers the NSW coast, so this isn't available for Bloomfield River (QLD).

Real tide predictions — Maritime Safety Queensland
For Bloomfield River, the tide panel shows a real harmonic tide prediction (Cairns storm surge station) rather than the Open-Meteo model, referenced to LAT chart datum: the published highs/lows, joined by a smooth half-cosine curve between each pair, so the curve and its labels share one LAT scale. Other locations still show the model curve and its turning points, since no equivalent real station is wired up for them yet.

Synoptic chart — Bureau of Meteorology
The national mean sea-level pressure analysis chart, reissued roughly every 6 hours. © Commonwealth of Australia, Bureau of Meteorology — see bom.gov.au/copyright.

Update cadence
Everything above is fetched every 30 minutes into a local cache by fetch_coastal.py, which then rebuilds this page as static HTML — so nothing is computed or fetched on page load. See the "last fetched" caption at the top of the page for how fresh the current data is.