December in Barra Mansa is the rainiest and the cloudiest month of the year. In December, the weather in Barra Mansa is typically warm. Average daily high temperature in December is about 26 degrees above zero. On average, Barra Mansa has 27 rainy and 4 sunny days in December. The rains are usually heavy. December as well as January, February, March, and October is considered the most uncomfortable time to visit Barra Mansa.