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.
National forecast responsibility changes quickly across these coasts and straits. Check the exact marine zone, tropical-system alerts where applicable, visibility and the latest local port or traffic notices.
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
Marine conditions, currents and dense shipping are separate parts of the brief.
The Malacca and Singapore straits cross Malaysian, Singaporean and Indonesian forecast responsibilities and dense traffic.
Compare MetMalaysia, Singapore MSS and BMKG for their respective sectors; current traffic-control instructions and visibility are separate operational checks.
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.
Weather jurisdiction and traffic control are separate
Split a southbound Malacca-to-Singapore plan into its actual Malaysian, Indonesian and Singapore-related source needs. METMalaysia, BMKG and MSS products are not interchangeable sector forecasts. MPA's vessel-traffic information addresses a different operational task. Current traffic instructions and navigational publications must be obtained independently; neither model agreement nor an AI summary authorises a lane crossing, port entry or a manoeuvre in controlled waters.
- METMalaysia shipping forecast — Select named shipping region; default Northern Straits of Melaka not every Malaysian coast
- BMKG named Indonesian waters — Bali/Lombok subdivisions and Raja Ampat/Misool sectors; select actual route
- Singapore MPA vessel traffic information — Operational traffic information is separate from weather products
A squall can change the visibility task
Sumatra-squall research is useful regional context, not a fixed daily schedule. Before the constrained segment, compare current warnings, available radar and recent visibility observations with the timetable. Keep the time reference of every layer visible. A low background wave forecast does not remove thunderstorm gusts or reduced visibility, and seasonal information cannot establish whether a rain band is currently crossing the vessel's route.
- Singapore CCRS / MSS Sumatra-squall research — Regional squall context, not a current squall forecast Direct product verification is limited; obtain the current issue from the issuer.
- Singapore MSS monsoon update — Seasonal context and indirect tropical-system influences; not passage clearance Direct product verification is limited; obtain the current issue from the issuer.
Do not derive local current timing from an ocean grid
Put charted navigation and applicable tidal/current information alongside the weather window, preserving their publication and time basis. If delay shifts arrival at a constrained segment, recalculate the full task rather than simply moving the start slider. Record which inputs remain unverified. This desk provides a framework for preparing information, not a pilotage plan, an exact current window or a substitute for current authority instructions.
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.