This is the second dispatch from our La Rochelle–Mediterranean delivery. Read part one here — the preparation, the crew, and why this passage is never routine.
Before a single line is cast off, the question that shapes everything is already on the table: what is the weather going to do? On a delivery passage from La Rochelle to the Mediterranean, that question does not have a simple answer — and in the last two years, it has become considerably harder to answer with confidence.
Two Years of Atlantic Weather That Broke the Patterns
Experienced delivery skippers work from historical patterns built over decades of passages. Those patterns still hold as a baseline — but since 2024, the Atlantic has been delivering anomalies with unusual frequency, and 2025 made the point emphatically.
In January 2025, Storm Eowyn tracked across the North Atlantic and struck the British Isles with wind gusts exceeding 100 knots in exposed locations — the most powerful storm system to affect Ireland and northern England in recorded history. By the time it had passed, the Atlantic was reorganising around a new blocking pattern that persisted for weeks, disrupting the standard westerly flow and producing back-to-back low-pressure systems tracking further south than usual. Charter and delivery operations across the Bay of Biscay were interrupted for the better part of a month.
Through 2024 and into 2025, the Mediterranean itself showed behaviour that veteran skippers described as anomalous: Mistral events that intensified faster than models predicted, unexpected summer Tramontane episodes off the French coast, and Aegean Meltemi patterns arriving late and then persisting well into October. For anyone planning a delivery that year — particularly passages timed around the Balearics or the Gulf of Lion — the routing windows were tighter and the penalties for being wrong were higher.
2026: The Pattern So Far
We are five months into 2026 and the picture has not simplified. The Atlantic has continued to show an unusual frequency of rapidly deepening lows — systems that the models flag as moderate and then intensify by 15–20 hPa in under 24 hours. The Bay of Biscay, never a gentle stretch of water, has been producing sea states that significantly outlast the wind events that generate them: the swell takes days to settle after a system passes, and a departure window that looks clean on the surface analysis can still put you into 4-metre residual swell at Finisterre.
The spring so far has also featured extended periods of high-pressure blocking over western Europe — good for Mediterranean sailing, problematic for Atlantic transits, because the Azores High positioned unusually far north compresses the southbound route and reduces the routing flexibility that delivery crews rely on to dodge systems.
The Weather Profile of This Route, Leg by Leg
Understanding why this passage is a weather routing challenge requires knowing what each section of the route actually does to a boat — and where the decisions have to be made early because there is no good option once you are committed.
La Rochelle to Cabo Finisterre — the Bay of Biscay
The Bay of Biscay has a well-deserved reputation, and it earns it differently depending on the season. In spring — which is when this delivery is running — the dominant risk is the rapidly deepening Atlantic depression. A low that leaves Newfoundland as a 1008 hPa system can arrive in the Bay in 36–48 hours at 985 hPa and falling, with associated gales on its southern flank that appear with very little warning in the 48-hour forecast window.
The tactical response is not to try to outrun the system — it is to refuse to depart into a marginal window. Bay of Biscay weather routing works on a simple rule: if the 72-hour GFS and ECMWF models agree on a clean window and the 48-hour NAM confirms it, you go. If they diverge, you wait. The cost of an extra 48 hours in La Rochelle is minimal. The cost of being caught in a developing Biscay gale in a new catamaran is not.
The other Biscay-specific challenge is the continental shelf edge at approximately 200 metres depth, running roughly 100nm west of the French coast. Where Atlantic swell crosses from deep water onto the shelf, wave height increases sharply and the period shortens. In a multihull this produces a motion that is uncomfortable and, if the watch rotation isn’t tight, fatiguing. We plan waypoints to cross the shelf edge during a settled period if possible, and we do it in daylight.
Cabo Finisterre to Gibraltar — the Iberian Atlantic Coast
Once past Finisterre, the dominant feature is the Portuguese Trade Wind — a reliable northerly that runs down the Iberian Atlantic coast from approximately June to September, driven by the Azores High. In May it is already established on most days but not yet consistent. You can have a 25-knot northerly on one day and a southerly 10-knot sea breeze regime the next as the Azores High wobbles.
The northerly trades are an extraordinary sailing wind when they arrive — a catamaran making 8–9 knots on a beam reach with the autopilot doing the work. But the same wind against a residual Atlantic swell produces a short, steep chop off headlands like Cabo da Roca and Cabo São Vicente that tests crew comfort and gear integrity. The Portuguese coast also has significant inshore current variations and several zones where shipping lanes compress: watch keeping standards here need to be just as rigorous as in the open ocean.
The Strait of Gibraltar — the Levanter and the Poniente
The Strait of Gibraltar is one of the most reliably deceptive stretches of water in European sailing. A glance at a synoptic chart showing settled high pressure across Iberia and Morocco tells you almost nothing useful about what the Strait itself will be doing.
The two ruling winds are the Poniente (westerly) and the Levanter (easterly). The Poniente gives you a clean inbound passage into the Med — wind behind, following sea, harbour entrance straightforward. The Levanter is a different proposition entirely. Funnelled by the topography of the Strait, it can produce 30–35 knots of wind in the narrows at Tarifa even when the open Atlantic and the western Mediterranean are both calm. The sea state it generates is steep, short and confused — particularly around Tarifa Point and in the approach to Algeciras Bay. In a new boat, in a Levanter, that is exactly where you do not want to be finding out about gear or handling issues.
In 2025, two of our delivery passages timed Gibraltar transits in what models showed as a settling Levanter, only to find the easterly reinforce at exactly the wrong moment. We now treat Gibraltar transits as requiring a dedicated 12-hour forecast window from a local Gibraltar weather station in addition to the regional models. Local knowledge and short-range forecast data matter here more than anywhere else on the route.
Western Mediterranean — Not the Easy Part
The common assumption is that once through Gibraltar, the hard part is done. It is not. The western Mediterranean produces its own catalogue of rapid-onset weather events, and the passage from Gibraltar to a destination in Spain, France or Italy carries its own specific risks.
The Mistral — the cold northerly that funnels down the Rhône valley and accelerates across the Gulf of Lion — can reach 40–50 knots with very little warning and produce seas that are disproportionately steep for the fetch involved. Models forecast its onset 24–36 hours out reasonably well, but its intensity and duration are consistently underestimated, particularly in the first hours of an event. If your destination is in the Gulf of Lion or along the French Riviera, departure timing relative to the Mistral forecast is the single most important weather decision of the second half of the trip.
The Tramontane, running down the eastern Pyrenees, affects the area between Cap Creus and the Balearics with similar abruptness. The Vendaval, a south-westerly that builds ahead of Atlantic depressions penetrating through Gibraltar, can affect the Spanish Mediterranean coast with little correlation to what the open Atlantic models are showing.
How We Plan Routing on a Passage Like This
The planning process for this delivery started before the crew left for La Rochelle. Not the minute-by-minute routing — that will be rebuilt daily from the boat — but the framework of decision points: where the passage can be interrupted safely, what the acceptable windows look like for each leg, and which legs have no safe intermediate stop and therefore require the most conservative timing.
- Primary models: ECMWF (high resolution, updated twice daily) and GFS (12-hour cycles). When they disagree on anything beyond 48 hours, we do not treat either as reliable.
- Swell: WW3 model output for significant wave height and period. Biscay swell runs on a different clock from the wind — we look at both independently.
- Routing software: PredictWind and Windy for visualisation; SAR-based GRIB files downloaded aboard for offshore legs where connectivity is limited.
- Updates at sea: every 6 hours, or whenever a model update becomes available. We do not go to sleep on a fixed plan.
- Bail-out ports: identified and briefed before departure. On this route: Bayonne/Saint-Jean-de-Luz (Biscay), A Coruña (Finisterre), Cascais (Portugal), Vilamoura (Algarve). Each one has been entered by at least one crew member before.
We have done this route, or routes like it, many times. The unpredictability of the last two years has not changed the process — it has reinforced why the process exists. You do not improvise a Bay of Biscay crossing. You plan it, you wait for the window, you commit when the window confirms, and you keep planning every six hours until you are tied up at the other end.
The One Thing We Know for Certain
We said it in the first dispatch and it is worth repeating: no two passages are the same. We know this route. We know what the Bay of Biscay can do, what Gibraltar can do, what the Mistral can do. And knowing it does not mean we will not be surprised. It means we will be less surprised, more prepared for the moment the surprise arrives, and already thinking about the response before we need it.
That is what experience in professional yacht delivery actually provides: not immunity to weather, but a practiced framework for managing it when it does not cooperate.
Next update from sea. Follow this delivery series for the full passage account.
← Part 1: Three Crew, a Brand-New Catamaran, a Thousand Miles of Sea