August in Sunyani is the cloudiest and the coldest month of the year. In August, the weather in Sunyani is typically warm. Average daily high temperature in August is about 26 degrees above zero. On average, Sunyani has 27 rainy and 4 cloudy days in August. The rains are usually heavy. August as well as May, June, July, and September is considered the most uncomfortable time to visit Sunyani.