September in Las Terrenas is the hottest month of the year. In September, the weather in Las Terrenas is typically hot. Average daily high temperature in September is about 29 degrees above zero. On average, Las Terrenas has 22 rainy, 5 partly cloudy, 2 sunny, and 1 cloudy day in September. The rains are usually heavy. September as well as January, April, May, and June is considered the most uncomfortable time to visit Las Terrenas.