August in Postojna is the sunniest month of the year. In August, the weather in Postojna is typically warm. Average daily high temperature in August is about 23 degrees above zero. On average, Postojna has 23 sunny, 7 rainy, and 1 partly cloudy day in August. The rains are usually heavy. August as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit Postojna.