January in San Marino is the cloudiest and the coldest month of the year. In January, the weather in San Marino is typically cold. Average daily high temperature in January is about 6 degrees above zero. On average, San Marino has 10 rainy, 9 cloudy, 7 sunny, and 5 partly cloudy days in January. The rains are usually moderate. January as well as February and December is considered the most uncomfortable time to visit San Marino.