August in Sunny Isles Beach is the rainiest and the cloudiest month of the year. In August, the weather in Sunny Isles Beach is typically hot. Average daily high temperature in August is about 30 degrees above zero. On average, Sunny Isles Beach has 26 rainy, 3 partly cloudy, and 2 sunny days in August. The rains are usually heavy. August as well as June, July, September, and October is considered the most uncomfortable time to visit Sunny Isles Beach.