January in Mostar is the coldest month of the year. In January, the weather in Mostar is typically cold. Average daily high temperature in January is about 3 degrees above zero. On average, Mostar has 14 rainy, 8 sunny, 5 partly cloudy, and 4 cloudy days in January. The rains are usually heavy. January as well as February, March, April, and November is considered the most uncomfortable time to visit Mostar.