August in Roswell is the rainiest month of the year. In August, the weather in Roswell is typically hot. Average daily high temperature in August is about 29 degrees above zero. On average, Roswell has 12 rainy, 11 sunny, and 8 partly cloudy days in August. The rains are usually heavy. August as well as January, February, and December is considered the most uncomfortable time to visit Roswell.