In short
The bise is a cold, dry wind blowing from the north-east. MeteoSwiss calls it Lake Geneva’s most characteristic wind: it sets in when high pressure covers the British Isles and low pressure sits over Italy. It whips up waves that spoil swimming, paddleboarding and boat trips, but kitesurfers, windsurfers and foilers love it.
Where does the bise come from?
According to MeteoSwiss, the bise sets in when high pressure covers the British Isles and low pressure lies over Italy. The cold air is channelled by the Swiss Plateau, which narrows towards the west, and speeds up as it reaches Lake Geneva.
Which direction does it blow from on the lake?
On the Petit-Lac (the Geneva end) and the Grand-Lac, the bise blows from the north-east. On the Haut-Lac, slowed by the Vaud Alps, it is deflected towards the mouth of the Rhône and blows more from the north-north-west (MeteoSwiss). The Lake Geneva lifesaving society (SISL) describes it as the lake’s most frequent wind and notes that temperatures drop quickly when it arrives.
How do you know if the bise is blowing today?
A cold, dry north-easterly that raises whitecaps on the lake: that is the bise. In My Lake, it counts as bise when the wind comes from the north-east (20 to 80°) and exceeds 15 km/h; the app then flags it at the top of the screen. The wind arrow for each beach shows where it is coming from.
Can you swim or paddleboard when the bise blows?
In a strong bise it is better to wait: it raises waves and currents along exposed shores. These are the app’s guidelines (not official standards):
- Swimming: above 25 km/h of bise, the rating stays at “Meh” at best.
- Paddleboarding: the rating drops once gusts pass 12 km/h and becomes “No” above 28 km/h (see paddleboarding on Lake Geneva).
- Boat trip: capped at “Meh” when the bise exceeds 25 km/h.
Why do kitesurfers and foilers love the bise?
Because it is steady and often strong. In the app, kitesurfing is “Perfect” between 22 and 40 km/h, windsurfing between 20 and 40 km/h. For foiling, a bise of at least 25 km/h gives a “Perfect” rating: it is the wind for downwinders, long runs carried by the waves. More in kitesurfing, windsurfing and wing foiling on Lake Geneva.
Lake Geneva’s water right now
Each beach’s water temperature is in the My Lake app, updated every three hours.