This is a pre-passage source and decision desk, not a current forecast or clearance to depart. The map is centred approximately on the area, not on your route or a forecast-zone boundary.
On a tidal Atlantic coast, the forecast wind is only one input. Check swell direction and period, tidal stream and the specific harbour or bar approach from current local publications.
1. Primary sources
Open current bulletins and warnings for every sea area on the route. These links are starting points, not a promise that each covers the whole location; if unsure, identify the issuer through WMO–IMO.
2. Route and local effects
Identify the French coastal sector and conditions at the tidal approach.
A Brittany leg can cross a tidal headland or channel before returning to a sheltered harbour. Locate the exact exposed point.
Use Météo-France marine for the correct coastal sector; combine it with local tidal stream and approach information, especially where wind opposes current.
How to use this source set
Start with the warning, then the marine text for the exact named area. If the route crosses a zone boundary, obtain both bulletins. Note issue and valid times, wind units and the meaning of wave height. Where a link opens an agency portal, navigate to its current marine product; a homepage is not itself a forecast.
Compare with an exposed station or buoy if available. Check its position and observation time: a sheltered station does not overturn a warning for an open channel. If a bulletin is missing or stale, identify the issuing service via WMO–IMO and defer the decision until current information is available.
Before-passage check
- Mark departure, exposed legs, arrival and feasible diversions; find the responsible named marine areas for each.
- Check warnings, issue and valid times; assess conditions when you expect to reach each leg, not only at departure.
- Compare wind and gusts, waves and swell, visibility, thunderstorms and local effects; do not infer a strait from a sheltered harbour.
- Compare recent observations where available, noting their time and exposure; a mismatch calls for another check.
- Set the next bulletin check, a reassessment trigger, an alternative and a backup communication channel.
Model map — optional
Windy is a third-party model display, not the issuer of official warnings. Choose a layer and check its valid hour and model run. Nothing loads until you click.
Without JavaScript, open the map separately.
If connectivity fails
Before departure, save the current official text bulletin and warning with issue time. Arrange another way to receive updates, such as an appropriate coastal broadcast, NAVTEX or satellite channel. A saved map cannot replace new warnings.
How to choose weather tools · All sailing areas
Scope: Source list assembled 25 September 2026; check its freshness and coverage before use. This public area guide is not a current personalised forecast, navigational notice service or safety verdict. Personalised forecasts with AI and experts are in closed testing; public booking is not open. The skipper makes the decision.
An Iroise leg is not the sheltered bay
For a Brest-area or Brittany coastal plan, locate the exposed headland or outer-water stretch before choosing the coastal marine text. The quiet water inside a bay does not describe the wind-wave interaction outside it. Compare the forecast direction with both the next cape and the destination's open side. Do not use a general Atlantic France forecast as if it resolved the conditions of every short tidal passage.
- Météo-France marine — French coastal and offshore bulletins; BMS warnings are separate products.
Three Shom products, three different questions
Separate tide predictions, observed water level and current information. Shom's oceanographic maps and oceanograms can add time-dependent model context, but the issuer explicitly describes them as raw simulations rather than expert-validated warning products. For a stream-sensitive headland, use the applicable current publication and chart reference. A high-water time copied from a nearby port does not establish slack at the headland or remove wind-against-stream uncertainty.
- Shom oceanographic forecast guidance — Raw model maps and oceanograms; not expert-validated warning products.
Reconsider before the tidal commitment
In a bay-to-bay scenario, compare the headland ETA, return possibility and next harbour under slower speed. Rebrief when the wind direction changes, sea state builds or the locally checked stream timing is no longer reachable. An alternative through another exposed headland is not necessarily more sheltered. Choose the next action from the actual remaining options, without presenting a static online guide as a current pilotage instruction.
- Météo-France marine
- RYA passage planning — Practitioner guidance on contingency, tides, vessel and crew constraints.
Editorial review of this material: 27 September 2026. This date concerns the page content; check current forecast issue times and validity at the original sources.
- France
Keep Atlantic tidal coasts separate from Mediterranean island and gulf planning.