January in Kos is the rainiest, the windiest, the cloudiest, and the coldest month of the year. In January, the weather in Kos is typically warm. Average daily high temperature in January is about 14 degrees above zero. On average, Kos has 15 rainy, 13 sunny, and 3 partly cloudy days in January. The rains are usually heavy. January as well as February and December is considered the most uncomfortable time to visit Kos.