December weather forecast in Rosario

December in Rosario is the coldest month of the year. In December, the weather in Rosario is typically cold. Average daily high temperature in December is about 6 degrees above zero. On average, Rosario has 20 rainy, 5 sunny, 3 cloudy, and 3 partly cloudy days in December. The rains are usually heavy. December as well as January, February, March, and April is considered the most uncomfortable time to visit Rosario.