September in Odessa is the rainiest and the cloudiest month of the year. In September, the weather in Odessa is typically hot. Average daily high temperature in September is about 28 degrees above zero. On average, Odessa has 14 sunny, 9 rainy, and 7 partly cloudy days in September. The rains are usually heavy. September as well as January, June, July, and August is considered the most uncomfortable time to visit Odessa.