December in Oskarshamn is the windiest month of the year. In December, the weather in Oskarshamn is typically cold. Average daily high temperature in December is about 2 degrees above zero. On average, Oskarshamn has 15 cloudy, 11 rainy, 3 partly cloudy, and 2 sunny days in December. The rains are usually light. December as well as January, February, and November is considered the most uncomfortable time to visit Oskarshamn.