August in Oita is the warmest month of the year. In August, the weather in Oita is typically hot. Average daily high temperature in August is about 28 degrees above zero. On average, Oita has 22 rainy, 8 sunny, and 1 partly cloudy day in August. The rains are usually heavy. August as well as January, February, March, and June is considered the most uncomfortable time to visit Oita.