- all year
The Bise is a cold, vigorous and persistent north or north-easterly wind blowing from the alpine mountains, that affects Switzerland and eastern France. The Bise is especially prominent in the Geneva area at the southwestern end of Lac Leman (Lake Geneva).
Anticyclones over NW or central Europe push the air through the gap this lake was formed in. Freed from the friction when over the water and funneled at the narrow end of the lake, it may reach 6-7 Bft. Being continental, it is a dry and, in winter especially, cold wind bringing snow and hail.
The Bise whips up the surface waters of Lake Geneva and in winter the sea spray encases the nearby vegetation under thick ice. During summer the dry Bise is a perfect laundry drier finding its reflection in the local folklore: "avec la bise, lave ta chemise", when the Bise blows, wash your shirt.