January in Adelaide is the sunniest and the warmest month of the year. In January, the weather in Adelaide is typically warm. Average daily high temperature in January is about 25 degrees above zero. On average, Adelaide has 19 sunny, 7 partly cloudy, 3 rainy, and 2 cloudy days in January. The rains are usually light. January as well as February, March, and December is considered the most comfortable time to visit Adelaide.