August in Myrtle Beach is the rainiest month of the year. In August, the weather in Myrtle Beach is typically hot. Average daily high temperature in August is about 29 degrees above zero. On average, Myrtle Beach has 16 rainy, 11 sunny, and 4 partly cloudy days in August. The rains are usually heavy. August as well as January and July is considered the most uncomfortable time to visit Myrtle Beach.