Weather & Routes

Supporting weather and route information — the captain decides.

Interisland passages in Hawaiʻi cross open channels where trades, swell, and current matter. HYANS gathers and summarizes NOAA forecasts, trade and swell context, and channel and port-approach notes as supporting information for captains and operators — so the people responsible for the vessel have a clear local picture to weigh.

Overview

Information to support judgment, not replace it.

HYANS reviews public NOAA marine forecasts and local conditions and packages them into a clear briefing — the trade-wind pattern, swell, the character of the channel you are crossing, and the timing considerations for a departure window or an interisland leg.

This is supporting information only. HYANS does not provide professional weather routing and does not replace the captain's and operator's navigation judgment. Forecasts change, conditions in the channels can differ from any forecast, and the final decision to sail, the route, and the timing rest entirely with the captain and operator, who retain responsibility for the safety of the vessel.

For the passages themselves, see Interisland Support; for the channels, see the channels overview.

What HYANS coordinates

What HYANS coordinates

  • NOAA marine forecast review, summarized in plain, decision-ready terms
  • Trade-wind, swell, and sea-state context for the relevant waters
  • Channel notes for interisland crossings and their typical character
  • Port-approach considerations for arrival and departure planning
  • Departure-window considerations for a passage or a long leg
  • Interisland timing context to inform an itinerary
  • A clear briefing the captain and operator can weigh against their own sources
  • Coordination with local sources — always as supporting information, never a directive
Typical requests

Typical requests we handle

Passage & timing

  • Departure-window context for a leg
  • Interisland timing considerations
  • Channel-crossing character and notes
  • Arrival and departure port-approach context

Conditions context

  • Current NOAA marine forecast review
  • Trade-wind pattern summary
  • Swell and sea-state context
  • How conditions may differ across channels
How it runs

Before arrival, in port, before departure

  1. Tell us the passage

    Share the intended leg or interisland movement, the vessel, and your target window. HYANS gathers the relevant public forecasts and local context for those waters.

  2. Review and summarize

    We review NOAA marine forecasts and conditions and package the trade, swell, channel, and port-approach picture into a clear, plain briefing for your window.

  3. Provide it as support

    We deliver the briefing as supporting information for the captain and operator to weigh alongside their own sources and professional routing tools. We do not make the call.

  4. Update as it changes

    If the picture shifts before departure, we update the briefing. The decision to sail, the route, and the timing remain the captain's and operator's responsibility throughout.

Before you contact us

What to prepare

Passage details

  • Intended leg or interisland movement
  • Target departure window
  • Vessel type and characteristics
  • Ports of departure and arrival

Context we should know

  • Schedule constraints on the window
  • Any comfort or motion sensitivities
  • The captain's own routing sources
  • Point of contact for the briefing
Questions

Frequently asked

Do you provide professional weather routing?
No. HYANS provides supporting weather and route information — NOAA forecast review, trade and swell context, channel notes, and departure-window considerations. It is not a professional weather-routing service and does not replace the captain's navigation judgment.
Who decides whether and when to sail?
The captain and operator. Every briefing is supporting information only. The decision to sail, the chosen route, and the timing rest entirely with the captain and operator, who retain responsibility for the vessel.
Where does the forecast information come from?
Primarily public NOAA marine forecasts and local conditions, summarized for the waters relevant to your passage. Forecasts change and channel conditions can differ from any forecast, so we present it as context to weigh, not as a guarantee.
Can you advise on the interisland channels?
We can summarize the typical character of a channel crossing and current forecast context to support planning. For the crossings themselves, see our channels overview and Interisland Support pages. As always, the briefing is supporting information; the navigation decision stays with the captain.

Planning a passage or interisland leg?

Tell HYANS the leg, the window, and the vessel. We will provide a clear supporting briefing for your captain and operator to weigh — the navigation call stays yours.