In September, the weather in Martinsburg is typically warm. Average daily high temperature in September is about 23 degrees above zero. On average, Martinsburg has 16 sunny, 10 partly cloudy, 3 rainy, and 1 cloudy day in September. The rains are usually heavy. September as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit Martinsburg.