September in Baltimore is the sunniest month of the year. In September, the weather in Baltimore is typically warm. Average daily high temperature in September is about 23 degrees above zero. On average, Baltimore has 17 sunny, 7 partly cloudy, 5 rainy, and 1 cloudy day in September. The rains are usually moderate. September as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit Baltimore.