The island enjoys a Mediterranean climate influenced by the presence of sea and mountains. It's characterised by sunshine, but also by some of the highest rainfall in France. The mild summer and clement winters are ideal for vines. The numerous winds play a regulating role on the climate and reduce the risk of cryptogamic diseases. The particular geography of the island creates a large number of microclimates, but the general climate is predominantly about:
MILDNESS: the annual isotherm is 17°C on the plains and 15°C in the mountains. It enjoys hot summers and mild (but frequently snowy) winters.
SUNSHINE: it gets between 2470 and 2885 hours of sunshine. This very good sunshine is a positive factor for maturing the grapes, in particular for the production of anthocyanins.
RAINFALL: Corsica receives 10 560m3/hectare/year, which places it among the rainiest areas in France. The distribution of rainfall isn't homogeneous across the island. The rainiest areas are the mountainous areas and the Cap Corse region.
AN EXCEPTIONAL SUMMER DROUGHT SITUATION: from 0 to 400 m in the area favourable to vine growing, the summer drought covers a period of 3.5 months on the west coast and 2.5 months on the east. Sun, precipitation, sometimes violent winds and significant temperature differences have shaped this natural setting in which, for several centuries, the Corsican wine-growing areas have been created.
The winds are numerous and sometimes violent (more than 200 km/h); they can be regional winds or local breezes.
They blow in all directions: the mistral which comes from Provence is dry and violent. The tramontana is a dry, cold wind from the Alps. The gregale originates from the Apennines and brings rain. The libeccio which comes from Gibraltar is the most common. It blows 85 days a year in Ajaccio, 147 days a year in Cap Corse, and 192 days a year in Bonifacio. It brings rain to the west. The sirocco, which can bring red sand from the Sahara, dries out the vegetation. Cap Corse and Bonifacio are the windiest regions and only have 16 windless days per year.
Regular sea and land breezes influence the climate. The sea breeze blows cool air from the sea from 9.00am until 7.00pm, but it mainly makes its presence felt in the afternoon, because the air is heated then. It has an effect on the work on the vines, which must be carried out before 9.00am or after 6.00pm. The sea breeze can be quite strong (which isn't the case for the land breeze). The land breeze blows air that descends from the mountains. During the night, the land cools faster than the sea and the air becomes cooler. It begins a few hours after sunset and continues to blow 2 to 3 hours after sunrise until the temperatures balance between land and sea.