September in San Andres is the hottest month of the year. In September, the weather in San Andres is typically hot. Average daily high temperature in September is about 28 degrees above zero. On average, San Andres has 27 rainy, 1 sunny, 1 cloudy, and 1 partly cloudy day in September. The rains are usually heavy. September as well as January, May, June, and July is considered the most uncomfortable time to visit San Andres.