Mistral (wind) from Wikipedia, the free encyclopedia
Mistral is an atmospheric phenomenon that occurs mostly in the winter and spring in the Gulf of Lion. It creates a cold, strong northwesterly wind along the coast, particularly from Montpellier to Toulon, in southern France and in the whole of Sardinia in Italy.

It is an example of a katabatic wind, which is caused by air that is cooled over the mountains by the presence of a high pressure system or radiative cooling. In the case of the Mistral, air is cooled above the Massif Central, central mountains of France, and the Alps. It then flows down into the Rhône valley, because its density is higher than that of the surrounding air. The presence of the Rhône valley creates a funnel effect, speeding up the current towards the Gulf.

In Marseille, on about half the days in the year the weather is characterized by the cold winds of the Mistral. Away from the Rhone valley, the effect is much less. These winds may affect the weather in North Africa, Sicily and Malta or throughout the Mediterranean, particularly when low pressure areas form in the Gulf of Genoa.

The same name is used for the North/North-West wind in the Adriatic Sea. This has similar geographic origins (katabatic wind) as its Gulf of Lion counterpart: air cooled over the Dinaric Alps Mountains flows down into the Adriatic sea, where it is known as Maestro or Maestral, ending as a cool North/North-West wind.