The sea on the Riviera can be flat as a lake in the morning and choppy by three in the afternoon. Two winds explain most of it: the Mistral and the sea breeze. Here is what they mean for a day on a rented boat.
The Mistral
The Mistral is a cold, dry wind from the north and north-west. It funnels down the Rhône valley and spreads over Provence; on the Var coast it turns more westerly. Météo-France speaks of a Mistral when the north-west wind gusts above 32 knots for at least six hours in a row.
It is usually strongest in the west, from Marseille to Toulon and Hyères. Further east, around Saint-Tropez, Cannes and Antibes, it often arrives weaker or does not arrive at all, depending on where the low pressure sits over the Gulf of Genoa. It is most common in winter and spring, but summer Mistral days happen too.
Two things matter on a boat. First, the Mistral blows from the land to the sea: close to the shore the water can look calm, but anything that drifts is pushed away from the coast, and the sea builds the further out you go. Second, it brings colder water up to the surface, so swimming can feel much colder than the day before. The old saying that it always lasts three, six or nine days is a myth, but once it sets in it can blow for several days.
The sea breeze
On a sunny summer day the land heats up faster than the sea. Warm air rises over the land and cooler air flows in from the sea to replace it. That is the sea breeze. It usually starts late in the morning, is strongest in the afternoon and dies down towards the evening.
For a day trip this gives a simple plan: leave early, enjoy the calm water for the crossing to the islands, and expect a livelier ride on the way back in the afternoon. On a small RIB this is the difference between a smooth trip and a wet one.
How to read a forecast
Look at the coastal forecast from Météo-France for your stretch of coast, and check both the average wind and the gusts. Wind is given in knots or on the Beaufort scale:
- Force 3 (7 to 10 knots): gentle breeze, easy for every boat.
- Force 4 (11 to 16 knots): moderate breeze, fine for most boats, small waves.
- Force 5 (17 to 21 knots): fresh breeze, uncomfortable on small open boats.
- Force 6 (22 to 27 knots): strong breeze, not a day for a beginner.
Also look at the wind direction compared with where you want to anchor. A cove that faces away from the wind is calm; one that faces into it is rolly.
When the weather turns
The operator has the final word on the day, because they know their boat and their coast. If they move or cancel your trip because of the weather, the terms are the ones agreed before you paid. Read Deposit and cancellation: settle them before you pay so there are no surprises.