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.
Distinguish an island or coastal bulletin from the wider METAREA text and its validity window. Long passages need a reliable method to obtain refreshed warnings offshore; a saved app screen is not one.
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
Island passages require the responsible coastal product and tidal information.
Zanzibar and the East African coast mix nearshore monsoon exposure with open crossings and shallow approaches.
Use Tanzania Meteorological Authority marine material for its published area and a METAREA text for an offshore leg; add current tide and local entrance information.
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.
Limit the Tanzania source to verified coverage
For a Zanzibar–mainland or Pemba plan, identify the exact TMA marine product, named coverage, issue and valid period before treating it as route evidence. The authority homepage alone is not that product. No verified current Zanzibar sea-zone bulletin is supplied here; obtain it and check its coverage before using it in the brief. A Kenyan or other cross-border continuation requires the relevant coastal service, not automatic extension of Tanzania's information.
- Tanzania Meteorological Authority — Authority entry point only; no exact live Zanzibar sea-zone product verified Direct product verification is limited; obtain the current issue from the issuer.
- WMO–IMO marine warnings and issuer directory — METAREA service selection; website can have delayed or interrupted products
Channel, reef and arrival timing
Separate open crossing weather from the tide/current and reef-approach task. A monsoon label cannot determine today's local current, entrance depth or usable transit time. Obtain the applicable chart and tide/current reference, retaining datum and time zone when relevant. Evaluate the destination's exposure to swell at the revised ETA; a land observation on an island does not establish channel or entrance conditions.
A realistic update-and-delay plan
Record how a fresh official marine warning will be obtained before departure and at the next reassessment offshore. Compare the proposed crossing with remaining at the presently verified stop until the missing source is available. If delay removes the independently checked arrival conditions, recalculate rather than preserve the itinerary mechanically. The page does not replace local entrance advice or establish a tide window from AI.
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.