September in Kihei is the warmest month of the year. In September, the weather in Kihei is typically warm. Average daily high temperature in September is about 25 degrees above zero. On average, Kihei has 21 sunny, 7 partly cloudy, and 2 rainy days in September. The rains are usually light. September as well as January, March, April, and May is considered the most comfortable time to visit Kihei.