September in Mount Juliet is the sunniest month of the year. In September, the weather in Mount Juliet is typically warm. Average daily high temperature in September is about 26 degrees above zero. On average, Mount Juliet has 19 sunny, 6 partly cloudy, and 5 rainy days in September. The rains are usually heavy. September as well as October is considered the most comfortable time to visit Mount Juliet.