January in Byron Bay is the cloudiest and the warmest month of the year. In January, the weather in Byron Bay is typically warm. Average daily high temperature in January is about 26 degrees above zero. On average, Byron Bay has 18 rainy, 6 sunny, 5 partly cloudy, and 2 cloudy days in January. The rains are usually heavy. January as well as February, March, April, and December is considered the most uncomfortable time to visit Byron Bay.