August in Fernandina Beach is the rainiest and the cloudiest month of the year. In August, the weather in Fernandina Beach is typically hot. Average daily high temperature in August is about 30 degrees above zero. On average, Fernandina Beach has 23 rainy and 8 sunny days in August. The rains are usually heavy. August as well as June, July, and September is considered the most uncomfortable time to visit Fernandina Beach.