The Alps form a climatic barrier in the country: to the North, which occupies most of the surface, the climate is temperate, oceanic or continental depending on the East-West orientation of the prevailing winds, with the four seasons perfectly marked and delimited. On the other hand, in the territory situated to the South of the 40 Alps, Valais, Ticino and Engadine ) a more mild climate, Mediterranean type is given.The prevailing winds in Switzerland are the Foehn and the Bise. The Foehn is a strong, warm, dry wind that occurs when a wind circulated over a mountain range to go down the other side, having thereby lost all their moisture. The Bise is a wind coming from the North, cold and dry, which is born in the northeast of Europe and blows through the continental Plains, especially reaching the area of the Swiss plateau.In the case of a country with a varied landscape and equipped with strong contrasts, there is therefore in Switzerland a variety of microclimates.There is also a high contrast with respect to rainfall. Annual rainfall is very high in the Alps and the canton of Ticino ( the order of 2,000 mm per year ) but are much more scarce in the Rhone Valley ( about 600 annual mm ).The cantons of Valais and Ticino benefiting from a high number of hours of sunshine per year ( around 60% ) while the Swiss plateau has around 50% in the summer to fall to 20% in winter.
