August in Yuzhno-Sakhalinsk is the warmest month of the year. In August, the weather in Yuzhno-Sakhalinsk is typically warm. Average daily high temperature in August is about 20 degrees above zero. On average, Yuzhno-Sakhalinsk has 13 rainy, 7 partly cloudy, 6 sunny, and 5 cloudy days in August. The rains are usually moderate.