April in Wausau is the rainiest month of the year. In April, the weather in Wausau is typically cold. Average daily high temperature in April is about 8 degrees above zero. On average, Wausau has 17 rainy, 6 cloudy, 5 sunny, and 2 partly cloudy days in April. The rains are usually heavy. April as well as January and March is considered the most uncomfortable time to visit Wausau.