Cassis marine weather: wind, swell and AIS traffic in the calanques

The Cassis marine weather is shaped by two landforms: the cliffs of the calanques to the west and Cap Canaille, the highest sea cliff in France, to the east. The wind accelerates, veers and gusts differently from offshore. This page brings together the wind measured right now over the bay, animated on the map, its hour-by-hour forecast, the Windy map of wind and waves, and the AIS radar of vessels around Cassis.

Further down, our skipper’s tips for the calanques of Port-Miou, Port-Pin and En-Vau, Cap Canaille and the bay of La Ciotat, and the checklist before you go.

The Windy map displays the European ECMWF model, centred on Cassis. Scroll the timeline to follow the wind hour by hour, and show the waves or swell layer: in Cassis, it is often the easterly or south-easterly swell that makes the sea uncomfortable, far more than the local wind.

The AIS map shows vessels that broadcast their position: calanque shuttles, sightseeing boats, merchant ships off La Ciotat. In summer, the bay and the entrance to the calanques are very busy with small craft that do not all appear on AIS: a visual lookout remains essential.

Between Marseille and La Ciotat, each area reacts differently to wind and swell.

The calanques of Port-Miou, Port-Pin and En-Vau

West of the port, these three calanques cut deep into the limestone cliffs. Port-Pin and En-Vau are the most beautiful, with their turquoise water. Sheltered from the mistral, they quickly become rolly in an easterly or southerly, when the swell comes right to the end. In summer, they are also very busy.

The bay of Cassis and the port

Open to the south, the bay is exposed to south-easterly and south-westerly swell. In a mistral, the relief partly shelters it, but gusts sometimes come down violently from the hills.

Cap Canaille and the bay of La Ciotat

With cliffs nearly 400 metres high, Cap Canaille creates downdraught gusts and areas of irregular wind. To the east, the bay of La Ciotat and Île Verte offer anchorages that are often better sheltered in a westerly.

Riou and the Marseille calanques

Further west, Sormiou, Morgiou and the Riou archipelago are very exposed to the mistral, which accelerates between the islands. An area to keep for calm days.

From Marseille to La Ciotat, the calanques are part of the Calanques National Park, the first peri-urban national park in Europe, both terrestrial and marine. Navigation is free but regulated: speed limit within 300 metres of the shore, anchoring regulated or prohibited in certain calanques and on Posidonia meadows, no-take zones around Riou, specific rules for carrying passengers.

Before you go, check the up-to-date regulations on the Calanques National Park website and use the DONIA app to anchor on sand. Respecting these rules preserves the clear water that makes Cassis so beautiful.

Cassis harbour when the sea gets up

Cassis harbour is small and its south-facing entrance becomes tricky when the south-easterly swell builds: waves sometimes break at the entrance and the surge rocks the boats alongside. In a mistral, it is the crosswind that complicates berthing. On those days, leaving from La Ciotat, which is better sheltered, or postponing the trip by a few hours makes all the difference. As everywhere, the live measurement and the Windy swell forecast are the two indicators to check before setting off. If in doubt, ask us for advice: we sail here all year round and know the pitfalls of the bay.

Cassis marine weather: good habits in summer

In July and August, the bay of Cassis is crowded with shuttles, charter boats and yachtsmen. Leave early, before the breeze and the crowds, keep a fuel margin to wait for a spot at anchor and have a plan B if the calanque you are aiming for is full. In the evening, the breeze drops and the light on Cap Canaille is magnificent: it is the best time to enjoy a calm sea.

Looking for waters just as beautiful but less crowded? From Marseille, the Côte Bleue and the Frioul islands offer wild coves, away from the crowds of the calanques. Discover our full-day boat trips from Port Corbières.