September in Ixtapa is the rainiest and the cloudiest month of the year. In September, the weather in Ixtapa is typically warm. Average daily high temperature in September is about 26 degrees above zero. On average, Ixtapa has 27 rainy, 2 cloudy, and 1 sunny 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 Ixtapa.