January in Mykonos is the rainiest and the coldest month of the year. In January, the weather in Mykonos is typically warm. Average daily high temperature in January is about 13 degrees above zero. On average, Mykonos has 13 rainy, 10 sunny, 6 partly cloudy, and 2 cloudy days in January. The rains are usually heavy. January as well as February and December is considered the most uncomfortable time to visit Mykonos.