September in Nha Trang is the rainiest month of the year. In September, the weather in Nha Trang is typically hot. Average daily high temperature in September is about 30 degrees above zero. On average, Nha Trang has 28 rainy, 1 sunny, and 1 partly cloudy day in September. The rains are usually heavy. September as well as May, June, July, and August is considered the most uncomfortable time to visit Nha Trang.