In September, the weather in Balikpapan is typically hot. Average daily high temperature in September is about 29 degrees above zero. On average, Balikpapan has 20 rainy, 5 partly cloudy, 3 cloudy, and 2 sunny days in September. The rains are usually heavy. September as well as January, February, March, and April is considered the most uncomfortable time to visit Balikpapan.