Compare north and south Bay, the Golden Gate/bar and the outside coast at their actual passage times, using separate forecasts and qualified tide/current information.
North Bay, South Bay and outside water need different products
Use NWS PZZ530 for its named Bay area and PZZ531 for water south of the Bay Bridge, then select the applicable outside coastal product if the track leaves through Golden Gate. The MTR marine desk helps locate the proper product and warning. Do not apply an inside-Bay wave description to the ocean approach, or a single point forecast to every crossing and receiving shore in the day's plan.
Read the separately labelled bar forecast
Where present, the NWS text identifies San Francisco Bar / Fourfathom Bank separately from the ordinary Bay forecast. Compare its sea and swell information with the actual entrance time and the applicable current context. Wave behaviour over the bar can differ from surrounding deeper water, especially with opposing ebb and swell. A reduction in wind alone is therefore not evidence that an outside return through the approach has become suitable.
A tide gauge is not the Golden Gate current
NOAA station 9414290 provides water-level and available meteorological products. Inspect the actual sensor and timestamp; use an appropriate current product separately. The height of high water does not establish slack in every Bay passage. Preserve datum and time convention when comparing water levels with a chart or ETA. Station quality notices also matter: historical data that have been withdrawn or flagged must not be silently reused in a retrospective weather case.
Visibility and changing Bay exposure affect the watch
Read the visibility and weather text alongside wind and waves, particularly before an ocean approach or busy Bay crossing. Identify what observations can confirm the relevant trend and what remains unseen between stations. Reassess the return after a direction change rather than copying outbound shelter. Plan watchkeeping and a checked waiting alternative if visibility or approach conditions deteriorate; this forecast desk does not replace charted traffic and navigation information.
Observations must match the stage being assessed
An offshore buoy, a waterfront wind sensor and a water-level gauge describe different variables and exposure. Do not average them into one apparently observed state for Golden Gate. Check sensor availability, observation age and whether the position represents the outside swell or sheltered Bay. If the approach lacks the required wave or current evidence, keep that limitation visible even when the regional models agree on the wind.
Compare a Bay outing with an outside-return scenario
Write two separate plans when considering an outside leg: an entirely inside-Bay alternative and the ocean departure/return. For the latter, evaluate both bar transits and a slower return ETA, not just the morning exit. Recheck warnings, current reference, swell period, light and available arrival arrangements at that later time. Keep the alternative specific and verified; proximity on the map does not certify a harbour or waiting place for the boat.
Official products by task
- NWS San Francisco / Monterey marine desk — Choose the correct bay, coastal or outside-water forecast, warning and observation. Do not interpret a sheltered bay product as coverage of the Golden Gate bar or an offshore passage.
- NWS San Francisco Bay north / bar text product — Read PZZ530 and the separately labelled San Francisco Bar / Fourfathom Bank section where present. Their domains and variables are not interchangeable; check the actual current issue.
- NWS San Francisco Bay south of Bay Bridge PZZ531 — Named south-Bay zone forecast. Use the appropriate neighbouring bay and coastal products when the planned track leaves this zone.
- NOAA San Francisco water-level station 9414290 — Separate observed water levels, tide predictions and meteorological sensors; read quality notices. This station is not a universal Golden Gate current or bar-wave sensor.
- NOAA Tides & Currents — Predictions and observations are separate products; choose station, timezone and datum.
- NOAA NDBC observations — Station map and timestamped buoy/coastal records; inspect sensor availability and exposure.
Waters and onward passages
- California coast
Swell direction and the next exposed headland matter alongside the coastal warning.
- US Pacific Coast
Match exposed legs, timing, approaches and realistic shelter options to the named zones and validity periods of the official forecast.
Countries and local sources
- United States
Choose a bay, coastal, offshore, Great Lakes or ocean product for the actual track.
Map orientation
The approximate area centre is not an approach waypoint, a track, a depth survey or a forecast-zone boundary. The third-party map loads only after your click.
Prepare a passage brief
Bring route timings, vessel and crew profile together with checked sources and reassessment triggers. Personal AI analysis and expert review are in invitation-only closed testing. An editorial geographic page does not extend the calculation service’s actual coverage.