In September, the weather in Tomakomai is typically warm. Average daily high temperature in September is about 20 degrees above zero. On average, Tomakomai has 16 rainy, 6 sunny, 6 partly cloudy, and 2 cloudy days in September. The rains are usually heavy. September as well as March, April, May, and June is considered the most uncomfortable time to visit Tomakomai.