The Swiss Alps act as a natural division between the temperate climate of northern Europe and the Mediterranean climate of Italy to the south. The impact of this divide can be felt within Switzerland itself, despite being a relatively small country. The country as a whole, however, has a fairly mild climate without extremes of heat or cold. Temperatures are warmer within Switzerland to the south of the Alps, with Ticino canton enjoying plenty of sunshine. However, Langnau in Emmental, in the canton of Bern, makes a counter-claim to that of Locarno in Ticinio as the sunniest place in Switzerland. Likewise, the canton of Valais also boasts of having the most sunshine in Switzerland. All this only goes to prove that every part of Switzerland enjoys its fair share of good weather! The difference between southern and northern areas is only that of two or three degrees Celsius on average, occasionally a little more.

The central alpine valleys tend to be drier than the rest of Switzerland, with the Alps creating their own micro-climate. High altitude peaks have snow year-round and summer skiing is possible on the glacier snowfields above Zermatt.

Despite this rather unique possibility, Switzerland experiences marked seasons. Summer and winter present strong contrasts but both are considered appealing and attract visitors to the Alps to enjoy outdoors pursuits. Summers exhibit a mix of hot, sunny weather and rainstorms. Although people from drier climates can find the weather uncomfortably humid during the hottest summer months this does not last the entire season. Typically, during July temperatures are between 12 to 20 degrees celsius in Zurich, with temperatures up to 25 degrees normal for Lugano in Ticino canton. At this time of year Zurich would also expect to see around 200 monthly hours of sunshine, and Lugano around 250. The highest average rainfall occurs in July in Zurich and is on average around 140mm. Lugano is wetter in August, with a typical monthly rainfall of around 200mm.

The Swiss spring is cool and fairly dry, often with plenty of sunshine to melt the winter snows. At night temperatures can still fall below freezing, however. In September the temperatures again fall and hours of sunshine drop. Autumn tends to be mild but wetter than spring.

Swiss winters often experience lasting snow cover topped up with frequent fresh snowfalls, especially at higher altitudes, making Switzerland a popular winter sports destination for over a century. In more recent years, however, winter snowfall has been less reliable across the Alps. Typical winter temperatures for Zurich are two or three degrees either side of freezing, and between freezing and 5 or 6 degrees Celsius in Lugano. Winter sunshine can be in the region of 50 sun-hours per month, averaging approximately 18% of the day, in Zurich during December. Lugano in midwinter could normally expect just over 100 sun-hours for the month. Weather trends place February as the driest month for Zurich, with around 70mm precipitation (whether rain, snow or hail) on average. In Lugano, January is the month of lowest average precipitation with under 100mm.

Warm clothes and waterproof outer layers are needed to be comfortable during a Swiss winter. A good pair of boots and a winter coat will be valuable, along with sweaters or fleeces, a warm hat and gloves. Thermal underwear is useful in helping those who find the cold to survive the chilliest weather. Even when it's cold outside, remember that in snowy conditions the sun's UV rays are reflected from the bright surface, and sunglasses and lotion will be needed to protect eyes and exposed skin.

Office buildings and public transport are heated, so dressing in layers is always a good idea in the colder months. On the other hand, don't expect air conditioning in summertime. A lighter waterproof jacket will be useful all year round, especially for those sudden summer downpours and thunderstorms, and it's also wise to have an umbrella close at hand. Lightweight casual wear and a good pair of hiking boots are ideal for days out to the alpine regions but city dwellers dress more smartly. Work wear is professional or smart casual according to the company, but shorts are accepted in some workplaces during the hotter months. Linen is also a good choice for hot weather business wear in Switzerland.

Alpine thunderstorms can be impressive or frightening, depending on your point of view. Severe rainstorms, which can include oversized hailstones, have the potential cause structural damage but rarely pose a threat to life if shelter is sought indoors. The floods and landslides brought on by heavy rain also bring about disruption. In winter avalanches can be a hazard, particularly in mountainous areas. Skiers are most at risk and there is a national avalanche warning system in place.

In common with other mountainous areas, Switzerland occasionally experiences a Foehn (Föhn) wind. This comes about when the moist air that is pushed up one side of a mountain range loses that moisture through rain and descends as a much warmer, drier wind. This creates low humidity and melts snow, frustrating winter sports enthusiasts. As with other similar winds, the Foehn in Switzerland is said to cause uneasiness and ill-health.