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.
Sea-area bulletins and archipelago or fjord conditions have different scales. In season, check ice and sea-level products; in narrow passages also examine current and visibility, not only mean wind.
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
Pair the sea-area bulletin with local channel and sea-level information.
The Finnish Archipelago Sea has many narrow passages, while the outer edge is exposed to Baltic waves.
Use FMI marine forecast, sea-level and seasonal ice products; check the actual channel against current chart data, not a broad marine grid.
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.
Give the outer Archipelago Sea a separate ETA
For a Turku-area island itinerary, distinguish protected channel sailing from the exposed outer-archipelago leg and its arrival. Use the applicable FMI shipping forecast and warnings alongside the marine map; a town forecast is not the same product. Compare wind direction with the open-water fetch and the final shore's exposure. A route that looks short on the island map may still require a demanding exposed crossing between sheltered sections.
- FMI marine-weather interpretation — Observations, marine forecast variables and buoy limitations, including winter removal. Direct product verification is limited; obtain the current issue from the issuer.
Do not label model curves as buoy measurements
FMI distinguishes observations and forecasts in the marine service. Read station location, variable and timestamp before copying a curve, and retain the sea-level reference. Significant wave height is not the maximum individual wave, and an outer buoy does not measure each narrow channel. Seasonal removal can interrupt buoy observations; missing winter data should not be reported as a calm sea or used to infer an ice-free route.
Reassess navigation workload as well as wave comfort
An inside-channel alternative may reduce waves but demand more visual recognition, chart work and attention to depth. Compare that workload with actual crew capability and forecast visibility rather than calling it automatically safer. Rebrief if a level trend reduces the assumed margin, visibility degrades or the arrival shore loses shelter. For seasonal ice, obtain a current dated product before treating the alternative as available.
- FMI marine-weather interpretation
- 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.