The Vallée de Joux (French pronunciation:[valedəʒu]) is a valley of the Jura Mountains mainly in the SwissCanton of Vaud. The valley also continues into France (Jura département) at its higher, southwestern, end. Located 30 miles (48 km) north of Geneva and northwest of Lausanne, its mean elevation is over 3,300 feet (1,000 m). There are three Swiss lakes in the Vallée de Joux: the lac de Joux (around 6 miles (9.7 km) long), the lac Brenet and Lake Ter. The French border runs along the northern edge of the valley until, about 10 kilometres (6.2 mi) west of the lac de Joux, the base of the valley becomes French territory. The valley then continues to climb gently towards the Lac des Rousses and the ski resort of Les Rousses.
The NE-SW orientation, and the 1,000 metres (3,300 ft) altitude combine to make for an especially cold winter climate. Indeed, the valley is sometimes called the Vaud Siberia. The coldest weather arises when the Bise wind, which comes from the North-East, is blowing.