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.
A long high-latitude or transoceanic leg crosses forecast responsibilities and update cycles. Separate meteorology from current chart, ice, port and navigation warnings, and plan a dependable offshore receiving channel.
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
A high-latitude passage requires specialised weather, navigation and communications planning.
Patagonia and Cape Horn require separate forecasts for channels, exposed capes and the open Southern Ocean.
Read Chilean Navy and Argentine SMN bulletins for their respective waters, then the high-seas issuer. Check warning validity and options for shelter without treating a channel reading as open-ocean evidence.
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.
Channels and Cape Horn are separate planning stages
A Patagonia itinerary through channels is not equivalent to an exposed Cape Horn or Drake approach. Use the Chilean Navy's channel product for the applicable interior leg, its marine/oceanic product for exposed waters, and the responsible Argentine/high-seas issuer where the track requires it. Keep national forecast responsibility and navigation permissions distinct. A familiar expedition itinerary is not a verified weather route for a particular departure.
- Chilean Navy channels and inland waters — Channel and inland-water forecast selection; original text requires chosen area.
- Chilean Navy marine weather — Distinct maritime, channel, oceanic, Antarctic and port-status products.
- WMO–IMO marine warning directory — METAREA issuer discovery; products may be delayed, national issuer remains authoritative.
Local calm does not settle the exposed cape
Retain outer swell period/direction, wind changes and visibility separately from channel observations. Terrain can make an interior site unrepresentative of the exposed turn around a cape. Current charts, local stream information and port-status instructions must accompany weather evidence. Do not supply a universal Cape Horn wind limit, a guaranteed lee or a numerical timing shortcut; boat capability and the actual synoptic evolution govern the operational question.
- Chilean Navy marine weather
- Argentine SHN product directory — Río de la Plata water-level, tide/current, wave, ice and navigation-warning products.
Reassess before the next exposed commitment
Test slower progress, a missed forecast reception and crew fatigue before the next exposed leg. If a new warning or swell direction removes the intended retreat, revisit the plan while usable shelter remains rather than waiting for an arbitrary model score. The Argentine Antarctic marine entry may require a live-service fallback when unavailable. A source-directory page is not specialist expedition clearance or proof of access to remote refuge.
- WMO–IMO marine warning directory
- Chilean Navy marine weather
- Argentina SMN Antarctic marine entry — Indexed Spanish/English marine entry; live page returned a gateway error. Direct product verification is limited; obtain the current issue from the issuer.
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.