August in Wilmington is the rainiest month of the year. In August, the weather in Wilmington is typically hot. Average daily high temperature in August is about 29 degrees above zero. On average, Wilmington has 16 rainy, 13 sunny, and 2 partly cloudy days in August. The rains are usually heavy. August as well as January, February, June, and July is considered the most uncomfortable time to visit Wilmington.