Provence-Alpes-Côte d'Azur

Provence-Alpes-Côte d'Azur fronts the Mediterranean on France's southern coast from the Camargue delta at the western edge through Marseille's working port and the long calanques cliff line east toward Toulon, Saint-Tropez, Cannes, Nice, and the Italian border at Menton. The tide here is the small Mediterranean signal — mean range at the Marseille port gauge is about 0.2 metres, with spring tides reaching close to 0.4 metres and neaps dropping near flat. The astronomical signal is genuinely tiny because the Mediterranean is a nearly enclosed basin and the Atlantic tide cannot propagate cleanly through the narrow Strait of Gibraltar. What matters more on a day-to-day basis is meteorological tide — air pressure changes lift or drop sea level by a few centimetres on a calm day, and the mistral wind that funnels down the Rhône valley and out across the Gulf of Lion can shift water levels 30 to 50 centimetres in a matter of hours, sometimes building rapidly when the pressure gradient steepens overnight. The Camargue lagoon system of the Étang de Berre and the Étang de Vaccarès runs a similar wind-driven regime where the astronomical tide is barely measurable. The calanques between Marseille and Cassis open up on the lowest predicted lows for the rocky-shore intertidal walks at Sormiou, Sugiton, and En-Vau. Sailing fleets out of the Vieux-Port, the working ferries to Corsica from the Marseille passenger terminal, the snorkellers in the Port-Cros marine reserve further east, and the night-fishing pointus around the Frioul archipelago all read the wider weather pattern more than the tide table. SHOM (Service Hydrographique et Océanographique de la Marine) is the authoritative French tide source; Open-Meteo Marine drives the gridded predictions on this site.