A weather window is enough time to complete the whole route in conditions within the limits of the boat and crew. Everyone has the forecast; the difference is reading it against the boat's and the route's criteria.
In the passage planner, pick departure, arrival and date to see each day's maximum wind, gusts, direction and wave height, rated for your boat type. Free. Open the passage planner →
Criteria first
- Wind
- The strongest wind the boat and crew can comfortably handle, and its direction relative to the route. A moderate headwind can be more tiring than a strong following wind.
- Sea
- Wave height and period; a short, steep sea is harder.
- Duration
- The window must cover the passage time plus a safety margin.
- Escape
- Ports to run to if the weather turns earlier than expected.
In our waters
- Meltemi: the summer northerly in the Aegean, strengthening in the afternoon. Heading north, early mornings are preferred.
- Lodos: south-westerly, raising a short, steep sea, especially in the Marmara and northern Aegean.
- Poyraz: north-easterly; decisive in the Marmara and the straits.
Decision points
- A few days out. Different forecast models are compared; if they agree, the plan firms up.
- Before departure. The official forecast and the latest model run; go or wait.
- En route. Reassessed at set points; the decision to turn for a refuge is made early.
Continue with this topic
- Meltemi and lodos calendar: A month-by-month picture.
- Ports of refuge: Marking them along the route.
Forecast sources
No single forecast is relied on when choosing a window. Several models and sources are compared; when they agree, confidence rises; when they differ widely, uncertainty is high and the decision reflects it. Official weather warnings are always checked.
What to look at
- Wind direction and strength, especially gusts.
- Wave height and period; a short, steep sea is far harder than a long swell of the same height.
- Areas where wind runs against current.
- The window's length: does it cover the whole route with a margin?
For the boat and crew
The same weather means different things to different boats and crews. A sea comfortable for a large, heavy boat can be exhausting for a small one. The decision weighs the boat's and crew's limits honestly.
Schedule pressure
The commonest mistake in deliveries is leaving in an unsuitable window to meet a schedule. The agreement with the owner states from the start how weather waiting is charged and that the departure decision is the skipper's; that removes the pressure.
Under way
Forecasts are updated regularly under way. If the weather turns earlier than expected, the decision to divert to one of the planned refuges is made before conditions worsen.
Records
The forecasts behind the departure decision are recorded; if needed they show the reasoning.
Local knowledge
Local effects such as acceleration around headlands and in channels often go beyond what models show; local knowledge and pilot books fill that gap.
Knowing a route's difficult stretches in advance lets them be timed for the calmest hours of the day.
Arrival conditions are part of the decision too: if wind and sea will make the harbour entrance difficult, arrival time is adjusted. A window must cover the arrival as well as the passage, since the hardest moment is often the last mile.
Waiting is often the right call, and it is explained to the owner with its reasons.
Patience is part of seamanship.