August weather forecast in Big Sky

August in Big Sky is the sunniest month of the year. In August, the weather in Big Sky is typically warm. Average daily high temperature in August is about 20 degrees above zero. On average, Big Sky has 13 sunny, 10 partly cloudy, 7 rainy, and 1 cloudy day in August. The rains are usually moderate. August as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit Big Sky.