The climate of Switzerland is heavily influenced by the Atlantic Ocean. The prevailing currents from westerly directions mainly deliver a mild, humid sea breeze to Switzerland. In summer, it has a cooling, in winter a warming effect, and most areas enjoy an adequate amount of precipitation throughout the year. The Alps are acting as a prominent climatic barrier between northern and southern Switzerland.
Climate of Switzerland
In the southern part of Switzerland, which is influenced mainly by the Mediterranean Sea, winters are considerably milder than in the northern part. Aside from their dominant effect as a climatic barrier between the north and south, the complex mountain range of the Alps additionally creates several different climatic regions.
Dry climate within the Alps
The inner-alpine valleys are characterised by a distinct climate, because they are sheltered against precipitation from both the north as well as the south. As a consequence, dry conditions prevail in these regions. Typical representatives of this phenomenon are the Canton of Valais in the south and the Canton of The Grisons in the south-east of Switzerland. While the average amount of precipitation is close to 2000 mm/year along the northern foothills of the Alps, in the Alps and in southern Switzerland, regional amounts in Valais range between 500 and 600 mm/year, and in The Grisons between 600 and 700 mm/year. In the lowland north of the Alps, the amount is close to 1000-1500 mm/year. Except in the Canton of Valais, the amount of precipitation during summer is nearly double that of winter.
Snow in winter
Starting at an altitude of 1200-1500 m above sea level, precipitation during winter usually occurs as snowfall, such that the area is often covered by a solid layer of snow for months. Snowfall is relatively rare in the low-lying areas of western Switzerland (greater Geneva area) and northern Switzerland (greater Basel area) as well as in the lowland in the southern tip of Switzerland. In these regions, winters without a layer of snow are not unusual.
Temperatures - ranging from Arctic to Mediterranean
Temperatures in Switzerland are primarily dependent on the level of altitude. In the northern lowland, the average temperature in January is close to 1 °C, and close to 17 °C in July. In the lowland in the southern part, the analogous average temperatures are 2-3° higher. At altitudes of close to 1500 m above sea level, the average temperature in January is close to -5 °C, and close to 11 °C in July. Locarno-Monti in southern Switzerland is the warmest city in Switzerland on average, with an available series of measurements and an annual average of 11.5 °C, while the Jungfraujoch Mountain at an altitude of 3580 m above sea level is the coldest place on average, with an annual mean of -7.5 °C. The highest measured temperature of +41.5 °C was recorded on 11 August 2003 in Grono in southern Switzerland, and the lowest measured temperature of -41.8 °on 12 January 1987 in La Brévine in the Canton of Jura.
Foehn wind as a special climatic element
Foehn wind is a special feature of Swiss climate. This wind that crosses the Alps creates pronounced mild and dry conditions on the leeward side. Especially the southerly Foehn that blows from the south toward the north is often associated with high wind speeds in the north and intense amounts of precipitation in the south. Foehn winds occur mainly between autumn and spring.
Recurring climatic phenomena
The climate of Switzerland is characterised by a number of special features – ranging from snowfall during spring, a cold snap in June to fog and Indian summer in autumn. The weather service MeteoSchweiz provides analyses and background information about the recurring phenomena.