January in Karratha is the rainiest and the cloudiest month of the year. In January, the weather in Karratha is typically hot. Average daily high temperature in January is about 33 degrees above zero. On average, Karratha has 15 partly cloudy, 11 sunny, 3 rainy, and 2 cloudy days in January. The rains are usually heavy. January as well as February, March, and December is considered the most uncomfortable time to visit Karratha.