December in Agios Ioannis is the rainiest month of the year. In December, the weather in Agios Ioannis is typically warm. Average daily high temperature in December is about 13 degrees above zero. On average, Agios Ioannis has 13 rainy, 10 sunny, and 8 partly cloudy days in December. The rains are usually heavy. December as well as January and February is considered the most uncomfortable time to visit Agios Ioannis.