September in Loreto is the cloudiest month of the year. In September, the weather in Loreto is typically warm. Average daily high temperature in September is about 21 degrees above zero. On average, Loreto has 17 rainy, 9 cloudy, 3 sunny, and 1 partly cloudy day in September. The rains are usually moderate. September as well as July and August is considered the most uncomfortable time to visit Loreto.