The Carinthian lake district is the warmest area in summer within the sub-alpine climate zone in Austria. In terms of sunshine hours and intensity, Carinthia is so well endowed by nature that we can justifiably speak of a sunshine province.

Lake W�rthersee combines the favourable factors of a mountain and lake climate(as compared with a maritime climate: lack of salt in the air and no strong winds): increased relative air humidity, increased heat and light radiation (thanks to the altitude and the reflection from the lake), little temperature variation (the lake acts as heat storage).

Temperature: Thanks to the lake's heat storage effect, the high summer temperatures last well into autumn. The climate is also milder than that of Alpine climates at the same altitude. A break in the weather, for instance, affects the temperature of the water of the lake considerably less than air temperature, with the result that the lake prevents early night-frosts. Nor is the air excessively cooled by thunderstorms and rain showers in the summer months, thanks to the heat radiation from the lake.

Rain: The wind-sheltered location, combined with the mountains to the south and particularly to the north, results in relatively low rainfall. It is true that most rain falls in the summer, but it is largely concentrated in heat thunderstorms or short showers.

Water temperature: The relatively high water temperature of Lake W�rthersee (up to 27�C) is worth more than just a mention. It is due to the unusually long and intensive sunshine and to the mountain chains surrounding the lake on all sides and largely fending off the rainfall. In addition, these mountain zones act as wind protection, preventing any significant cooling of the water, since the temperature movements of a lake are largely influenced by airflows. In addition, Lake W�rthersee is fed by very few mountain streams with their cold water; instead, very many underground springs supply water at a constant temperature. Otherwise, the lake has no significant inflow or outflow, with the exception of the Glanfurt.