September in Pasto is the warmest month of the year. In September, the weather in Pasto is typically warm. Average daily high temperature in September is about 20 degrees above zero. On average, Pasto has 22 rainy, 5 partly cloudy, 2 cloudy, and 1 sunny day in September. The rains are usually heavy. September as well as January, February, March, and April is considered the most uncomfortable time to visit Pasto.